Once you go Quaiffe, you won't go back. it is 10X better than the stock diff. It is hard to get the car to spin out of a corner with the Quaiffe. I could get the car to spin so easy going around a corner with the stock diff. The Quaff gets the rear end to hook up so much better.
I was one of the first to do the Quaiffe, and had to change a bearing as it was not correct from new. It was a simple fix though. They do take some fine tuning to get correct, but once there, they are great.