I often go to Cargame S2 or S1 when I want to drive these cars, which is quite often in my case
You'll usually find me there running my FXO as hard as I can usually finishing top 3 in class. It's really addictive, and wish that there were more servers running it rather than GT classes (as well as events with them)
RB4 lacks the top end speed, but nearly makes up for it with its AWD in the corners.
XRT can be fun if you can handle it and should be able to have good fights with FXOs
FXO is hard to beat in longer races with its stability and speed.
RAC is hard to control by almost every one, those who are able to get a grip on it though can really fly.
In all it is probably my favorite class