Takayuki Kuroki (yes, the one wearing glasses driving the R33 Skyline GT-R) manages to defeat the Blackbird. Cleanly. For a character that only appears in one story arc (the R200 Club, 1st and 2nd half), this is an impressive feat. He could have beaten the Devil Z too had his engine not overheated/over-revved and blown.
Not only that, but losing to Kuroki sent Shima into a Heroic B.S.O.D.. Yes, a one-shot character defeats a recurring character, and in the process breaks his motivation.
Akio Asakura (this one, not the previous one) manages to tame and control the Devil Z by the end of the story. While it seems mundane, keep in mind, he is the first person to do so without getting killed.
Wangan Midnight Maximum Tune
Cleaing all of Story Mode without losing a single stage.
"You have got a new title: Undefeated Winner of the Highway / Undefeated Highway Dominator"
And if you do so with the Mitsubishi Pajero in MT 4:
"You have got a new title: From Paris To Dakarnote A homage to the Paris-Dakar Rally once dominated by the real life Pajero"
Every battle with R200CLUB has "CCR" Motoki and "JAPAN" Tezuka attempting to wreck your car, only to crash as a result. From Maximum Tune 4 onwards, they see you as target practice for when they take on Reina's GT-R later, with a cutscene partway through showing them spectacularly crashing into each other.