Good luck. I know HACKr and Sucahyo and some people like that resorted to using devices to get into the game's coding to find hidden stuff. I don't have any such device, but to anybody out there who does: I'd like to know why there's a difference between lowering a car in GT and lowering the same car in GT2. Same goes for dampers.
In other words, if you lower a car too far and I think raise its dampers high in GT, it'll start losing speed (especially over bumps) and I've always assumed this is because PD either programmed the tires to rub into the car's fenderwells, or the bottom of the car is supposed to be scraping, or suspension travel is so limited that the car's tires are now losing contact with the road. In GT2, none of this happens. There's rarely any effect on speed for any of this.
In my opinion, PD scrapped these effects either because they didn't have enough time to put them into GT2, or for whatever reason this stuff was too difficult to implement for 700+ cars that are in this game.
Good luck, as I said.