:: bigger rear sprocket gives you less top speed. Not much difference, but slower. Smaller rear sprocket is faster and bigger front is faster. If you want power, send in your cylinders to fast or hjr and they will port them for you. Plug wires will not do anything for speed. The aftermarket CDI will help a little giving you like 100 more rpms but you won't notice more speed. But for power, porting is the best bang for your buck.. Also check to see if you have a neon green boost bottle and a purple power band. If you don't have those, your banshee will be slow