Callaway C12
I must say I was not impressed with the Callaway C12.
It was very competent in a straight line but through the bends felt like a lumbering giant. I tried it on the 'ring, and it really couldn't keep up with Europe's finest. There was lots of understeer which really made the 'ring a hard course to drive fast on. For me it's a typical American car. Sure footed in a straight line, but rolley poley round the bends, more of a motorway blaster than a track day car.
If I can spare the cash in GT mode I might buy one and try to dial out the understeer, as this car could be so much better.
Ginetta G4
At first I hated this car, as when ever you try to take a fast corner flat out the rear end would break away. So I had to develop a different approach so I could get the most out of this fun little English sports car.
I get the impression that each car is different in GT4. Unlike previous versions of the game, you get a real sense that you can't drive each car the same way. Maybe most people do this on a subconscious level, and they don't notice they are doing it. But for me, I really noticed how different each car was last night. This is a impressive feet by PD, and the turn greatness of this game is starting to shine through past the number of cars and tracks.