I have been using a OS TR in my NTC3, with excellent results. The thing I love most about OS engines is that you can be 1/4-1/2 turn off on your needles and still make good power. The reliability of the engine is top notch. Normally where I race we run 10 min mains, and 1/2 of the field wont make it past 5-6 min due to engine flame outs, overheating, ect.
Not that I'm bashing Novarossi, They make unreal power, but they require more needle massaging to make them sing sweet.