I have tried ABS in several RACES in different surfaces, normal tracks and rallies, with different cars, RB4, FXO, XRG and FZ5. My conclusion is like TC, ABS it is not useful in race, it is easy to race without ABS than with ABS, and can be faster without ABS, but for noobs I think that will be easy to use ABS, but you will learn more without any helps.
The conclusion is, XRG with ABS don't make faster than XFG