I did the electric conversion on my Savage 25 and did some mods to make my tranny a bullet proof 3 speed along with a few mods to the diffs to make them bullet proof also. I changed the rx to a 4 channel so I would have mechanical brakes and put in the reverse module. The reverse module is a VERY fragile thing and DID not last, so I have NO reverse, but I DO have 3 speeds and INSANE does not even come close to the speed this thing has now. As for durability, the only thing that has broken so far is the dog bones. They twisted in half. Replaced them with some a friend made out of some Titanium and the cups also.