Just done a mild shunt mod on my 6 MOSFET 48v controller to see if there are any gains. Indeed there are, acceleration is noticeably improved and it holds speed on the throttle a little better, and this is just from a thin tinning of solder around the middle. So to make these gains permanent I'm after a 48v 500w controller with 25a current, so far KT seems the most economical, any other options that are reasonably prived