all ways of making your cart go faster fool your speedo . over 25 mph it will not be accurate . the after market motors make your speedo show 1/2 speed .
I switched my speedo to kph then programmed my controller so that the number showing is actual mph . so now my speedo will show actual speed up to 41 mph .
Daves mm will do the exact same thing and installs in about 10 minutes . I have reprogrammed dozens of controllers but wouldn’t recommend it to most people unless they want to do other mods .
start with an mm .
p.s. if you want even more power after that , I would look at an extra battery ( if your using 8v batteries) or lithium before I would spend any money on a different motor .