i have the lastest atomik prox out with the better hubs and better rear sproket and so forth. ive had a orion agb29 with the bigger sprokets and i can say that my prox with the 37tooth rear sproket eats it. so first u should start with a 37 rear sproket then once you get that sorted buy an IRK (inner rotor kit) then your bike will be flying with just lest then $150 spending on it.. have fun
cheers
PJ