As far as tuning goes, here are some of my experiences:
Springrate: You usually want this pretty high for quick response, the front and rear springrate both also affect how far the rear-end will swing out when you shift your weight, so don't just adjust the rear alone trying to get it to throw out easy.
Dampers: Pretty high in the front to maximize traction. The lower you go in the rear, the quicker the rear-end will come out. I'd adjust the rear after setting springrate & LSD, then drive the car and feel it out. Every car is different, that's the most important thing to remember in tuning.
Camber: Usually a degree or so higher in the front than in the rear. I like to stick with about 4.5 / 3.5. Camber gives you that sort of feeling like you never really have traction even in a straight line, it's almost more unstable but in a good predictable way.
Stabilizers: I found that these prevent side-to-side weight transfer way too much. I always leave my stabilizers at 1 but raising it in the front wouldn't necessarily be a bad thing. In the rear, though, you want that lateral weight transfer for setting in to the drift, linking corners, feint, etc.
Brake balance: I found that this one played a very strange role in the handling of the car. It seemed to affect much more than the brakes to me, in fact I found that a higher setting would often make the car put down more traction somehow and push the car further toward the inside. So if you're having problems with sliding off the course at the exit, you might try playing with this setting. As far as the difference between front and rear, I usually keep them the same, I found that it makes the car more nimble during braking.
LSD: I still have a lot to learn here, but here are some of my thoughts... A higher accel, compared to initial & decel, will increase the initial set-in of the car (assuming it's a RWD). Sort of like the thing about springrate. If this difference is too high for your springrate setting, you will have trouble breaking traction in the rear using the throttle, and the car will fling itself sideways very easily. If it's too low, the throttle won't seem to be able to push the rear-end out enough mid-corner when you're starting to power through the apex. For decel, I usually put this at the same as the initial.
TCS: Hahahaha
ASM: Do I even need to say it?
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Oh yeah, you can check out some of my settings that I use here:
http://pergatory.net/gt3/settings.html
I've been meaning to add to the list of cars but just haven't had the time. Anyway, hope you found some of that info useful.