I'm not sure if this forum supports addon suggestion but I'll give it a shot.
I was testing out LFS Tweak, with my XRT with huge rims and 1100 horsepower and I thought, this is way too unrealistic.
Maybe LFS Tweak could use a different program, and make a realistic addon program. Where it lists all the parts you can add onto your car. Bigger PSI turbos, intercoolers, anything you could addon to your car to make it bigger, and faster, without means of pushing 9000 CC Engine for a 1000 horsepower unrealistic beast. Catch my drift?