The 300x is for sure more powerful. Shauns reads definitly make more power on top i gaind 400 rpm on top from stock 250 reed cages the throttle body doesnt make that much difrence on its own being that the reeds on a stock motor just cant swallow the (cfms) extra air. The most bang for your buck that will blow your mind will be a lightend flywheel and a hydrotech tuner shaun can get all of that done for u also very important to get the most from the tuner u need a simon poppet diverter u will remember me once u do these 3 things