To make stronger diffs, do I just change the housing to aluminum? Or do I have to change gears too. I have seen a lot of confllicting info about it on the traxxas forum. So I decided to talk to you guys. I have heard about shimming although, I am not really sure how to do that. School is starting soon, so I want to keep costs down. Right now I have the HV but eventually want to upgrade to the 9l.