Errrrr, where to start?

The MC18 flywheel is more retarded than the MC21, so by fitting the MC21 flywheel, it should beef up the upper mid range and peak power, but at the expense of over rev. You'll also need to watch for detonation.

NSR pipes are not based on RS pipes. Well, ours aren't anyway. The RS pipe is designed to peak at 12,250~12,500 rpm, where as the NSR porting is aimed more towards the upper end of 11,000. this mismatch makes for a seemingly powerful engine, but in reality it just makes it peaky, with a major drop in bottom end power.

If you want to fit RS pipes then you'll be needing to get in the engine with the dremel and give it a good whizz. ven then you won't exploit the full potential of the pipes because of the RS's ignition and carbs. for your info, NF5 pipes are the closest fit, although not perfect as the engine position in the NF frame is different to that of the NSR.

The RS piston doesn't go straight into the NSR (unfortunately). It's shorter than an NSR piston and used a different size gudgeon pin, so the standard gasket must be replaced with a thinner one to bring the timing back in to spec and you must use special piston pin bearings.

Blah blah blah.........