about the tyres, it may not be as realistic as in real-life, i.e. taking hours to wear out a hard set, but the way the wear can increase if you keep sliding, or can last longer if you drive sensibly, depending on how you choose to drive, is very good and you can actually see a difference if you alter your driving style. say you are getting 8 laps by driving wildly, if you tame yourself a bit you might be able to get 10, and that can affect your whole strategy for that particular race.
also, in GT4 Prologue, when they show the "making of", it says Kazunori drove every car in the game.
RIP Jules, never to be forgotten. #KeepFightingMichael