Originally Posted by BSCFlash

Are you racing or bashing? The 15/43 offers more than enough speed for the tracks we run on. Our local hotdogs run 14/43 or 15/45-- that's it. If you want more speed than that for bashing, experiment with bigger pinions, or, depending on your esc, try 6s in lieu of 4s for power. I don't know how big of a pinion you can squeeze in there because no racer I know has ever tried anything bigger than the 15.