I have a Hyper 7 RTR that I converted not to long ago. The hardest thing I had do deal with is that I wanted to use a Ofna plastic 52t spur gear. RC-Monster (Mike) made an adapter to fit the plastic spur on to the diff for me. It works very well. I don't know what you have planned, but you might want to consider something like that too. Otherwise the the metal spur will eat up your pinions.