I had Harold install a Quaife in my ride a few months back, and I couldn't be happier. It wasn't cheap, but one of the best mods I have done. Service was top notch, and I have been back twice for further work on my E92.
Also nice to tool down the back roads on the way home!
JB4, BMW Perf. Exhaust, DCI, Strut Brace, KW Series 1, Quaife LSD, Black Kidneys.