Real tires are $400-600 for two, I wouldn't call that diminishing returns or excessive effort/money. I went from spinning in 3rd on Nittos to hooking in 1st on MTs. Now I want more power.
Also shens if you are having grip issues in an Evo with 500 AWP :awe:
It also depends on the car/engine. Maybe past 400 HP starts getting complicated and expensive in a hurry and gives diminishing returns on a fwd 4 cyl. Not so for a Supra/Cobra.
And I don't know what's up with the ricer comments, I think your cars kick ass. Ricer is the Z I see around town with a triple deck spoiler, body kit, and fart can, and stock 268 HP.