[Darren69]

The S4 and S4R are detuned and have softer cams than the 916/996 SBK's so they have much more mid range and nearly as much top end, which really is too much for an unfaired bike. Like the SBK's though they do benefit from a less restrictive exhaust and some mild ECU tuning to really get the best out of. Go take a sorted one for a test ride. There's a nice S4 Foggy for sale on ebay if you want the ultimate S4 madness package! A sorted S4R or RS would be even better. S4RS for me please! Get one before the prices go stupid, asking prices for a nice S4RS have already gone up 2-3K in the last few years. S4 and S4R's are still decent money though.