I bought one from HP. Have the AT with bolt on quaife option. Bought just the QUaife unit and switched out the internals. Installed it at my shop. Took about six hours. My tech said it was the easiest Diff he has ever done considering this is a BMW and was expecting it to be hard....er. lol. Really tho, no special tools required. Have been running it for about a month with no issues. Ass-end comes out really nice. Does some sweet controlled drifting too now. No more loss of control in wheel spins. Take off is noticeably improved as well. If you cant find anyone up there, feel free to hit me up in SJ. We'll do it for 500-600 bucks.
