I think the biggest problem is as mentioned above.. the ones who will stuff nitrous onto every car they own, and use it all the damn time like the "Boost" button in Burnout 3. To a lot of us, that's like cheating. A lap time isn't going to mean as much if you "boosted" your way to the finish line. The game isn't necessarily about speed as it is about skill. The "NOS RULEZ!!" crowd are the same ones who are complaining that PD put the Model T and Daimler Carriage into the game, when they could have put in something faster. For them, it's all about how fast you can go. And these people will miss out on 90% of the game because of it. They'll consider the game "finished" once they have a few LM cars and the F1 car. While the real GT'ers will be playing until GT5 trying to find some elusive 70's "crap car" that we really want to drive.
John said: "A tricked out compact isn't a disgrace to the car community..", which is partly true. But I think it depends on what kind of "tricking out" is done to the car. Cars that are all about the bling-bling are the ones that people tend to frown on (or in my case, laugh at). But there are other types of tricking-out.. there was a car in the parking lot here at my apartment the other day, parked right next to me. It was a Nissan of some sort, although it had no other name on it, so I'm not sure what model it was. And it was quite tricked-out.. BUT, not on the outside. There was no spoiler, no neon, no flashy stickers, no body kits, none of it. But, according to the small stickers on the window, the inside had been totally overhauled. There were half a dozen names on that car, and one of them was Nismo (it's a Japanese company, some of you may have heard of it.. hehe). What that told me was that this "ordinary" sedan could probably whoop just about anything you put next to it. This car wasn't built for looks, it was built for performance. And THAT I can appreciate.