Originally Posted by bdebde

The Pro version really doesn't need much in the way of upgrades. You may need a bit stiffer springs if you run a heavy battery/motor combo. The spur gear should be just fine as long as you are running the RC-Monster hardened pinions. Drop Mike an email, ask him if he has a motor mount for a Muggy (see this post). The Muggy center diff is exactly the same as the Sportwerks.