[dradernh]

Originally Posted by XutvJet

Diffsonline is showing $2,700 for a built diff with a Wavetrac unit plus $95 to ship. Then when you receive the diff, you have to ship back your stock diff which is another $100+. So, at the end, you're out nearly $3,000.

The M Performance LSD is a high quality 3-clutch unit built by Drexler and setup perfectly for street and light track use. Most any racer would say a clutch-based LSD is the ideal setup, but it does wear out over time. Expected service life is 80K+ miles. I paid $2,050 for mine last year from my local BMW dealer and it was installed for $450. You can find the M Performance LSD online from most BMW dealers for around $2200-2300 now and most will knock 10% off.

I paid $2,235 for the diff, $58 to ship the OEM unit back, and $300 for the installation, for a total of $2,593 compared to your $2,500. Whether another buyer can achieve the same installed cost, I do not know. It's my opinion that installed LSDs in the $2,500-3,000 range that meet the buyer's needs are a bargain for the performance improvement they offer.

I've had clutch-based diffs in track and race cars, so I'm familiar with how they behave on the track. I think it's useful to remember that no one here is racing, and that the OP says he's not going to be tracking his car. Given that, is it your belief that a clutch-based diff is a better choice for a street car - or vice-versa, for that matter?

FWIW, I accepted Dan's choice of the Wavetrac because I didn't want a unit that would require maintenance, and I knew it would be entirely satisfactory for me on the track. I suspect that whoever goes back to a BMW dealer for an M Perf diff rebuild is going to be in for a mild shock when the bill is presented - I'm guessing clutch-rebuild type pricing.