I have had a Quaife on for about a year. Went with it mainly due to the long track record compared to the Wavetrac. Wanted a gear driven differential due to the low maint. One thing I did do was have the diff. oil changed about 1,000 miles in.
Best mod I have done, and should be a "must have" if you want to take advantage of any power and suspension mods. Other than on a wet road once or twice, I haven't seen the traction control lights since putting it on.
JB4, BMW Perf. Exhaust, DCI, Strut Brace, KW Series 1, Quaife LSD, Black Kidneys.