Has anyone used Yukon Gears in their mustang? I am either putting 3.73's or 3.90's in my car this winter and I was told to get everything through Randy's Ring & Pinion. They only sell Yukon Gears though. Also is it extremely difficult to install gears and set them up right with the proper backlash? Is it something a mechanically inclined 17 year could do? I plan on getting a book or video that goes into detail explaining the process but i'm not sure how hard it is.