If he does it himself make sure he has all the proper tools for doin it. Or has two sets of gears and plans to get a shop to do the second set. I bought a stang with a home job done, 1500.00 dollars later I got new gears cause the ones in the car were toast, there was also filings that took out the seals and bearings which in turn killed my axles. In short, have a shop do it, it's warrantied and easier.