Would this cause serious fuelling&performance problems? know the R6 exhaust has a valve that creates variable backpressure to tune torque curve, would this system be compatible with an NC30?

The only bit you could fit would be the 'can' or silencer section. Assuming it's the right size inlet there is no reason you couldn't.

The valve is in the collector section, there is no way you could fit this to the NC without some serious re-engineering and pipe work. You'd need a new ECU to be able to control it and you'd need to program it, don't think anyone has tried an exup valve on an NC.

Druid