[RKDinOKC]

I like the PSD differential on my GTS. It's uses inputs of speed, direction, accelerometers, and steering input to determine whether to and/or how much to lock up the rear differential. It also works in conjunction with the ABS that is programed for maximum braking, not just keeping the fronts from locking up. The system is not intrusive at all.

The Cayenne S is another story. PSM won't let it slide or drift. Even if you turn it off, it comes back on when you hit the brakes. Takes some getting used to. But, then again, despite what some do with them, the Cayenne is NOT a track vehicle. It is the tow vehicle to take the track car to the track. On the cars, PSM is supposed to let the car drift up up 15 degrees before overriding driver input.

My 81 GMC Jimmy was full time 4 wheel drive. The rear end was positrack and the transfer case was limited slip. With the big tires, if you made enough turns in the same direction it would take up all the slip between the rear wheels and one front wheel and stop dead in it's tracks and kill the engine. You would have to back up, staighten it out and go forwards and back a few times to reset the slip lock to continue on turning in that same direction. It usually happened when trying to turn into a parking spot after cruising round and round all in the same turn direction. Did happen once when i was just turning a corner though.

Drove a Boxster with TC, not PSM and it was mostly brakes and throttle to keep you out of trouble, and very intrusive when trying to drive fast. TC did not allow for any drift.