yeah cant go wrong with rollcentre mate
ive just had a custom one done for my S2, full FIA national spec, and didnt break the bank
these are however, as far as i know, only suitable if you want to bin the rear seats like i have, i didnt need mine anyway so any excuse
All depends what car it is for and what you are planning to do, i.e a saph that wants rear seats might be better off going for a different brand of cage than someone who wants a stripped S2
hope this helps mate
Scott