This post and my post about music kinda inspires me to make my own racing game (for the squillionth time). I've always got hung up on trying to make super realistic physics, but I reckon I'd be wise just to simulate the rudimentary physics and get a game going. Need 3D movement though. Not gonna stick with the lame 2D environments. Gotta go all out for jumps and hills. The trouble comes when you start thinking of rotational velocity and rolling the car ... ahh well.
If I can get the engine running nicely, I'm sure I can get modellers in on the deal, and I can do the music and sound effects myself. Back to the drawing board. Btw, if I do actually do this (chances are I'll start and get bored and give up), I'll definitely implement some of your ideas porky. Customisable engines (these will just be variables anyway), skirts, spoilers, scoops, exhausts, paint jobs, etc. Although I'm thinking more offroad style ...
We'll see.
Insiiiiiiiiiiiiiiiiiiiiiiiide!