Game Breaker / Gran Turismo

Gran Turismo has long famously billed itself as "The Real Driving Simulator" with an emphasis on simulating how cars actually drive in real life. Because reality and the laws of physics don't care about Competitive Balance and can't be nerfed as easily as a game can, this means that some of the cars available have become legendary for being able to easily defeat their competition, even despite attempts by Polyphony Digital to nerf them. Sometimes, certain quirks in the in-game economy can also leave players awash in far more cash than the developers intended.

Series-wide/multiple games

• The 1998 Suzuki V6 Escudo Pikes Peak Special rally car has almost 1000 horsepower and four-wheel drive and weighs less than a ton, enabling it to crush anything no matter what they do. The only drawback is the understeer, which happens if you're dashing through a corner way too fast. In 2, it was practically unbeatable. They nerfed it in 3 by making it nearly uncontrollable and removing the course it was designed for, but a skilled enough player with a good setup could still use it efficiently, and it could be tuned to 1843 horsepower, enough to get it to 430 km/h while still outdragging all other cars. A properly tuned Escudo could literally break the game in 3 by popping a wheelie and then suddenly going FTL. They had to nerf it again in 4 to get it stay as a curiosity rather than a Game-Breaker. Thankfully, in 5, while it's not the game-breaking racing machine that it was in 2, it finally became controllable again to the mild delight of fans.
• The 1998 Toyota GT-One Road Car in 2 and 3. It's easier to get than the race car: In 2 it's purchaseable from Toyota's Special lot at any time for 1 million credits (While the race car can be had as a prize from the GT World Championship or for all golds on the Super License); in 3 it can be had as a random prize from the GT World Championship in the Amateur League (While the race car is a prize from the much longer GT All Stars or Dream Car Championship in the Professional League). Once you have one, it has 600 horsepower (only slightly less than the race car), weighs 900 kg, and has insanely good handling, making it a Master of All among road cars. In 2, once you have it tuned, it has the highest top speed of any car in the game barring the HKS Drag 180SX while still being plenty maneuverable. You can win the events where only unmodified cars are allowed (except Roadster Endurance in 3), or slap a turbo upgrade on for up to over 1000 horsepower. The only downside versus the race car is that in 3, front downforce can't be modified, which will make it slower at Test Course. Still not as good as the Escudo all round, but not far off, and for half the price in 2.
• For early to mid-game, the stock Dodge Viper, in its many iterations, is a Disc-One Nuke. It's essentially the same car as the racing-class Team ORECA model, but it costs one-tenth as much and, unlike the racing model, is fully upgradeable, letting you reach up to 1000HP+ in some games. In the first game especially, it is the best production car in the game. 440HP stock, 100 more than most of the others, cheap, and it handles quite well thanks to the game's weird physics. On the Normal Car Cup, where only stock production cars are allowed, it demolishes the competition. In 4, meanwhile, an Old Save Bonus can let you buy it as your first car.
• The Nissan Skyline GT-R, throughout the series, has done a similarly comprehensive job on the competition, to the point of causing a Red Stapler effect and making it a popular gray-market import in real life. The 1996 NISMO 400R and (debuting in 4) 2002 R34 models are probably the best of the bunch. While it lacks the Viper's pure horsepower and top speed, it makes up for it with superior cornering ability and all-wheel drive.
• The 1989 MINOLTA Toyota 88C-V race car, obtainable in 4 by winning the El Capitan 200 Miles race (which you should definitely win by using the Cadillac Cien or the Toyota RSC Rally Car) and in 5 by completing both races in the Like the Wind endurance event. Don't be fooled by its deceptively cute looks — this car easily gives the Formula GT a run for its money with its ludicrous speed and handling. Even the most incompetent B-Spec Bob can then win the Nürburgring 24 Hours in the Minolta and win the aforementioned Formula Gran Turismo F1 car, itself a ludicrously overpowered Game-Breaker. To this day, it is unquestionably the fastest LM Prototype in the game. Ironically, it never won a race in real life.
• The Red Bull cars, starting with the X2010 in 5 and continuing with the X2014 in 6 and the X2019 in Sport, are pure fantasy vehicles designed by Polyphony Digital and Red Bull Racing to be the ultimate race cars, without consideration to cost, safety, fuel consumption, regulations, or anything else. They combine the best features of the Formula Gran Turismo and the Chaparral 2J, and then put that on steroids. If you can master them, then they are unstoppable. They do the 20km Nürburgring, one of the most difficult race tracks in the world, in well under half the Real Life record, taking most of the corners at speeds of well over 300km/h.
• The Seasonal Events in 5 and 6. To make up for the pitifully slim payouts in the regular A-Spec mode, they really increased the prize money (to compare, the first 90-minute long endurance race gives you about 120,000 credits with a win, while a 10 minute Seasonal Event usually gives you thrice that). They also don't require any licenses, and some of them only require easily obtainable cars like a Honda Civic. Even coming in second or third gives you more than the said endurance race. Much easier than grinding the Like the Wind event. Sadly, with the shutdown of the games' servers in 2014 and 2018, respectively, these are no longer available.
• 5 and 6 have a Play Every Day feature where, every time you put your game disc in your PS3, as long as you don't pass a day without playing the game as well as having a PSN account, your monetary awards will increase from 110% to a maximum of 200% if you manage to keep playing the game after 5 days or so have passed. This means that every time you win a race, you'll get absurdly high payouts, especially if you manage to get first place and even more so if you did the Seasonal Events. If you plan to do this, keep that in mind if you're going to play your favorite racing game, because once you're away from playing it, the opposite effect will happen, and after 5 days have passed, you're back to 110%.
• Any higher-tiered car you can enter into the A- or B- Spec races where "No Restrictions" is specified for the car type in terms of performance. For instance, you can throw in anything from the Skyline GT-R to the Bugatti Veyron to one of the Red Bull Cars into the Sunday Racers event, which is supposed to be for low-powered sedans. Or the McLaren F1 into the British Hot Hatch event, a race for UK-made hatchbacks. No wonder Polyphony Digital added PP limits for career races in 6...

Gran Turismo 1

• The race version of the Dodge Copperhead Concept Car is completely unfair. It is as fast as cars like the Subaru Impreza Rally Edition and Toyota Castrol Supra GT, but weighs as much as a Formula One car. The result is a killing machine that smokes everyone while turning on a dime.
• The Subaru Impreza Rally Edition has outstanding handling and acceleration, but a fairly low top speed of only 141 miles per hour... until you mess with its gearbox. You lose little to no acceleration power and you have a rally car outspeeding true tarmac racing cars on high-speed tracks like the High Speed Ring.
• Once fully tuned, the Nissan R33 Skyline, Mitsubishi GTO Twinturbo, and Toyota Supra RZ all churn out over 900 horsepower. You could just outspeed everyone to victory with an advantage that big. All were nerfed in subsequent games to the 6-700 HP mark.
• The TVR Cerbera LM prize car has about 600 horsepower, weighs less than a Miata, and has an unbelievable amount of grip and downforce, even compared to the other LM cars. Not even the fairly cheaty AI Castrol Supra in the GT World Cup can come close to catching it.

Gran Turismo 2

• JGTC (GT500 class) cars. For some unknown reason, they have 150-200 more horsepower than their real life counterparts, resulting in them being faster than a Group C car. What's more, you can win one by simply tuning a Skyline R34 up to 580 horsepower and racing the Grand Touring Races. However, the Project A-Spec mod downplays this by nerfing the cars to their real world power outputs.
• Winning the race at Red Rock Raceway in GT All Stars gets you a TVR Speed 12 every time, which sells for half a million a go. Get the Unisia JECS Skyline from the Grand Touring race at Midfield Raceway mentioned above, and you'll win quite easily and soon be able to afford the Escudo Pikes Peak mentioned top.

Gran Turismo 3

• The F1 cars were designed as the ultimate race cars, and are the only cars allowed in the final event. Long before then, however, they can still break the game easily since you can get one almost immediately. You have a 25% chance to get one from each endurance race, all of which are unlocked upon getting the IA License, and as mentioned under Disc-One Nuke, the Roadster Endurance is essentially a beginner-friendly endurance race as long as you have racing tyres for it.
• Endurance races in general. Excluding the Roadster Endurance, which pays less and awards you with another Miata if you don't get the F1 car as a result of requiring less money and effort to get into, prize money ranges from 150,000 to 500,000 Credits, and the prizes are all amazing even if you don't get an F1 car. All you need is one really good car from one and you can easily beat most of the other Endurance races, as well as any races the car is eligible for. ^note The Roadster Endurance and Trial Mountain Endurance are the exceptions, as both require normal, untuned cars (tyres notwithstanding so racing tyres are permitted), and the Roadster requires Miatas.
• The Mazda 787B stands out, being the fastest car in the game (besides the 6 F1 expies) and also the only Group C car on it. And unlike the Escudo, it can actually be controlled at high speed.

Gran Turismo 4

• The 1970 Plymouth Superbird and the 1965 Pontiac GTO for historic car events, in which 5 40-hp alleged cars are put against these 400 hp V8 monster.
• Once you unlock it, the Formula Gran Turismo. You have to beat the Nürburgring 24H Endurance event to unlock it, but once you do, you have an Ace Custom F1 race car that can enter most events and walk to the podium unopposed.
• The Chaparral 2J. Let's put it this way: in real life, it was banned from motorsport due to its vacuum downforce system giving it such a towering acceleration and cornering advantage, and this game doesn't simulate the mechanical problems that plagued it on the Can-Am circuit. As an opponent, it often made the All-American Championship unwinnable. It costs a third of the price of a Group C car, and is so easy to win with that even B-Spec Bob can win the Gran Turismo World Championship. And it is small enough to take part in World Compact Car Races, which is designed for nimble, small, but painfully slow Joke Cars. Thankfully, it was nerfed in 5. Or, rather, it was put in the used car dealership lottery and became twelve times more expensive.
• If you want to make a lot of money in little time, follow these four easy steps:
  1. Win first rally, get Cadillac Cien concept car.
  2. Win 2nd rally with Cien, get Toyota RSC Rally Raid Car.
  3. Sell Toyota RSC Rally Raid Car for a quarter million.
  4. Repeat steps 2 and 3 for tons of cash.
• The game's "rules" are easily bendable in a lot of cases. If you're into earning A-spec points for a Self-Imposed Challenge, you'll find that installing racing suspension to improve cornering does not at all affect points rewards. Want to use a car as a rolling wall to make a turn at higher speed? The game usually will not object. This also extends into cases where driving across grass to avoid a chicane does not cause a penalty at all.

Gran Turismo 5

• If you purchased the Signature Edition, then you got for free six exclusive "Stealth Model" cars. They consist of black versions of a Nissan GT-R GT500, a Honda NSX GT500, a Mazda 787B, a McLaren F1, an Audi R10 TDI, and a Mercedes-Benz SLS AMG. Made especially moreso by the fact that repairs on those cars from racing damage are dirt cheap. And they can still be upgraded (with some limitations) at the Tuning Shop. See just how fast the upgraded Audi R10 TDI can go in the "Like The Wind" Challenge here (or here if you prefer a view from the cockpit).
• The borrowing system let you borrow high-performance vehicles that any of your friends on the PlayStation network had and use them for races. If one of your friends has an X2010, then you're probably having a lot of fun.
• Rain. That's right, a weather condition is a Game-Breaker in 5. The 1000km of Suzuka, the La Sarthe 24 Hours, and the Nürburgring 24 Hours (being on the only tracks to have variable weather) become incredibly easy, as the other cars are absolutely awful in wet weather. The Nissan R35 Touring Car makes it even easier, being a four-wheel-drive car (and thus very controllable in the wet) that is tuned to compete with the Group C legends.

Gran Turismo 7

• Update 1.11 introduced three half-hour long, high-paying World Touring Championship events at Tokyo Expressway East, Sardegna Road Circuit, and Circuit de la Sarthe after finishing all Menus that reward up to 825.000 credits for a race win with a clean race bonus. While this was already an effective way of grinding money, the thing that brought these events to full-blown game-breaking status is that it's possible to detune the SRT Tomahawk X all the way down to 595 PP with clever tuning of gear ratios, ballast, and ECU, cutting over half of its stock PP and making it eligible for all three events without actually sacrificing much of its performance. This means that these events can now take as much as 10 minutes less to complete and are also made MUCH easier thanks to the Tomahawk X being still fast enough to lap the opposition as many as 5 times despite the detuning. This, coupled with the Clean Race Bonus requirements being much more lenient than normal, means that it's easy to get around 2.8 million credits in just an hour of playtime. Polyphony tried to address the issue in update 1.13 by making a few changes to how PP are calculated, but players quickly found out a virtually similar tune that passes the PP requirements and is even faster than the old one, leaving many to think that this issue is unlikely to be resolved in a moment's notice; said tune is substantially the same as the old one, just with ECU and power restrictors set to 90% instead of 70%. Update 1.15 it is completely patched meaning that the player can't use the Tomahawk X anymore. The 1.21 update brought back the glitch but at this time, the tires were only limited to Comfort Hard ones and it is somewhat slower than the previous building. However, a next update it patched it again and for good.

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