There really is no need to mod stuff, just be on top of your diff shimming n it always works out. Another tip is when building the rear diff don't try and get clustered with having the arms on. Just take it all apart and just use the case the diff and the pinion and the cvd. This way u can have an accurate feel when u hold the out drives and rock the part that holds the Pinion back n forth. U just need a minor tight spot when it's new and it will break in nicely.