I think it really depends on a lot of things spec and maintenance and driving style included. If your a Kevin and drop the clutch at every given oportunity a standard 130bhp rs turbo is unreliable....
With a decent set of conrods, efi and an ib5 gearbox and you don't drive like a spanner (all the time) then a well spec'd 230-250 imo is perfectly suited to the road. People always quote 200bhp as this is the maximum output of 80% of the rs turbos on the road, its more or less the natural limit of MFI.
But things don't really get fun until your past 200bhp
Rob,