Which MM system do you have right now? If you are already running it and have beefed up the tranny and other stuff, then you are probably good to go.

A buddy of mine, although I don't recommend it, is running a 4600 system on 3S lipo. It runs surprisingly well and with proper cooling measures, it runs at a nice cool temp too. He throws it in my face all of the time, because I thought he would have all sorts of problems. Just another reason why the 4600 is my favorite.

I think that going with a larger motor, like an L can Feigao, will result in lots of broken drive train parts. Even the L can motors are beasts.