Sorry to hear you are having problems with your NSR AHUG030...
I've only had my '96 Repsol MC28 SP for ~ 3 months and covered ~400 miles (shame on me). But my bike has been 100% reliable (touch wood - no, not that kind of wood - though the bike does arouse me somewhat! ).
It does appear these bikes can be a bit fickle, so I'm leaving mine well alone. It has M Max pipes and that the only mod I can see, though it must be deristricted (wire splice?) as it goes to 180KPH and beyond. It runs really well, and I've had great fun on it so far and can't wait to have a proper go on a race circuit next year.
Quick comments on the bike from a new NSR rider - The engine is incredibly smooth for a little 250, and from ~8,000rpm it pulls like a good'un all the way up to 12,000 rpm, with a surprising amount of useable torque from as low as 5,000 rpm. Though in the higher gears the engine can bog down, so more revs are required here for good progress. The SP close ratio gearbox keeps the power sweet when the next gear is selected on full throttle runs. The lightweight SP chassis feels way more capable than me, and the standard brakes have a nice progressive feel, and tonnes of stopping power (not surprising with only 138Kg + me to haul up).
Oh, and in terms of looks and exclusivity, it beats just about everything hands down...