All the NSR's are grey imports. Unlike Suzuki, the NSR was never distributed under the Honda Australia flag. Makes getting parts a wee bit harder, too.

The wire splice should give it a lot more go, you could check to see if it's been done correctly. I believe there are two steps to delimiting the MC21. It's all on this site, just have a look under TUNING.

Haven't ridden a RGV in many years, and the one I rode had power valve problems and I wasn't impressed with it (and my current bike was a CBR250!) So I can't comment. Should be able to get the NSR up to around the same horsepower pretty easily with just a few mods. I.e wire splice, pipe and opening the airbox (and a rejet). Make sure your power valve is adjusted correctly too. I prefer the HRC method for setting this as I adjusted via the factory method, and when I checked it against the HRC method, it was way out!

So, read the TUNING section so you're up to speed.