IMHO the Vette is the best ISI car yet. I haven't had issues with understeer at all. It's been a fun car to drive, very lively through the corner and has big balls. It's just fun to drive. Any GT car has a tendency to push if you don't drive it right but I don't think it has to do with the tires or the contact patches. I've noticed in rF2 a certain problem I have when I push hard and brake too late where I chew up the front tires. I have the exact same problem in GTR Evo as well. But that has nothing to do with tires or the contact patch that's just me.