[burgermeister]

The theoretically ideal roll center for a car where no other limitations apply appears to be near ground level. It minimizes any ride height changes caused by jacking loads (high roll centers cause the car to rise during cornering) or rake changes (if the roll centers are different front / rear). And as a practical item, F1 cars would appear to have roll centers near ground level, and that's as high performance as I can think.

For a street driven car, chances are any RCH that doesn't make ridiculous compromises for streetability is low enough that it doesn't have any significant effect (as Flieger suggested). On the other side of the coin, roll centers at axle height are the domain (and bane) of swing axle suspensions, and they're terrrible for tire wear as well as rear end stability.

I don't know much about tuning race cars, but I imagine RCH could be used to tune around certain limitations, accepting the compromises that come with that approach (or perhaps undoing compromises made for the roadgoing version of the car). But I'd also imagine there are easier ways to tune around most things?

Off roading seems like it is more of a terrain (dirt) shearing exercise than a keeping tire patches parallel to the roar surface exercise, and terrain shearing is probably not so dependent on camber. And obviously 12" - 24" of suspension travel is is more desirable than perfect geometry when traversing huge bumps at speed.