I'm sorry, but I am calling BS on this one. Post some video, or quit blowing smoke.
Dude, are you blind or what?
So far I've seen only a couple GT5 races which reminds something like races, the rest 95% is all about half of AI cars overtaking me on straight and then in the first turn I hit the wall of barely moving AI idiots.
Go to Supercars event, High speed ring race for example, I was 5-th with first try beating Veyron by far with 80-th Mugen Civic (214 hp). I could easily beat 4-th Zonda C12 if I defended a bit (cause I passed this Zonda in every turn during the whole race).
Do you see this as anything even barely close to normal?