The Entire Red Line race. THE....ENTIRE....REDLINE.....RACE! It's so over the top it makes all the stuff on the Gurren Lagann Awesome page seem like an everyday occurrence by comparison. It must be seen to be believed, especially the climax of the race.
The very first shot in the movie features what may be the most gorgeously detailed illustration of a pile of pistachio shells to ever appear in an animated movie. This is how you know the animators weren't fucking around.
Lynchman catching up to his FULL SPEED vehicle, ON FOOT.
Lynchman is also the Batman Expy...except with hotblooded-ness.
Three words: PLATINUM NITRO CHARGE.
The entire ending, with the bomb in JP's vehicle accidentally being triggered, and only serving to make it go faster. Then JP manages to win the race in a photo finish, despite his vehicle finally exploding, and only winning because his pompadour crossed the finish line first.
The entire design of Godwing. In the flashbacks it's seen that it use to be a conventional racecar. But as of the latest Redline it's one gigantic badass boast; it's rider has no cockpit to ride in, and is instead the literal nose of the car, it's less of a car with jet engines and more of a jet engine with wheels bolted on, and whereas other cars have their nitro boosters as complex pieces of machinery, Godwing's Nitro is triggered by Machinehead biting down on the nitro packet. It's stated that most people can't even survive the concussive speeds of a Steamlight nitroboost, and Machinehead literally eats them.
Near the end of the race, Frisbee refuses to blow up JP's car again, that is in spite of Inuki giving him a massive check to change his mind and then siccing his goons on him when he says otherwise
Frisbee: I want to see him do it, just this once! He's so close, I want to see win for once in his life!