As above

The RS shell i built up was converted to st170 climate control etc -front heated screen - blah blah - everything works fine - but massively fluctuating voltage 13.8 - 15.0 at idle - idle not affected drastically - although where revs should drop between gears stays high - tried -63, 065 and 075 battery same result- so my question(s) : Whats the difference between st and rs alternator apart from amps ie fitment - case of just changing pulley over?

With rs alternator problem is worse with sub/amps etc ...no charging problems or starting probs...starts first time everytime ....can iget a higher amp alternator - cant seem to find apart from St or diesel cheers guys!