I've got the Powertrax like Mark said. Overall, I'm happy with it...especially at the strip. It does exactly what it is supposed to there. As with all things though it is a compromise for all around performance. Compromise #1...Thou shalt not get on it hard in a turn. Compromise #2...it doesn't unhook on turns from a stop all that easily because, well..you are accelerating after all and that's when it is supposed to lock. That can be a little hard on your tire life. They have different springs that control the locking and unlocking pressures which might control that. Compromise #3...in a straight line and at a constant speed, if you drop a wheel into a groove or rut, it will unlock quite easily. If you then give it a little gas, it pops back into lock, sometimes with a bang. No biggie, though, just a little noisy at times. As for turning into a parking space or cruising thru the parking lot turns, you can hear it clicking but it's not bad at all. Nothing like the stories I've heard about Detroit lockers. OTOH, maybe I'm a little more tolerant of the compromises in order to get what I want when I stand on it.

Check with Alan's gear works, he's the dealer in the area. He says that the cogs do wear down over time on a street car. Not really surprising though.

Tony