Sandman, Good to know. What i'm trying to accomplish is to modify my car to provide a great ski rig, so I can go where I want and not be worried by the weather. Canada, Washington, Montana and Idaho are the spots I can frequant. I thought the B9 Tribeca has a limited slip differential like the Outback 3.0R, but I maybe wrong. It seems that the Tribeca traction control is a braking system nanny controlled by the ECU. Slowing the spinning wheel to transfer torque to the wheel with traction. If used a lot, I would imagine it would cause the brakes to get hot. Maybe enough heat to warp the rotor if snow hits the hot iron rotor.
My idea is to add a rear ATB LSD like a Torsen or Wavetrac. The Wavetrac has a sliding locker inside the hub to help transfer torque from the unweighted wheel to the traction wheel. You know if one wheel is off the ground, it reduces the ATB LSD torque transfer to the weighted wheel. Clutch styles work well with the inside wheel off the ground, but not a Torsen. Clutches wear out in those style and replacement is almost as costly as a new clutch LSD including labor.
However, back to the electronics of the B9, if you had a ATB LSD in the rear, would that screw up the steering on the road giving the car more understeer. It may also do the same rounding a corner in icy weather, making the electronics work even harder in front to help brake the inside tire sending torque to the outside pull the nose of the car back in line with the steering angle. I'd just be spending money and making the car harder to drive. If I could figure out how the Outback 3.0R is setup, maybe I could duplicate that Subaru effort.
i am not using my car like you are, but I could find myself in a difficult spot by driving through the mountain passes in a severe snow storm like back from Montana to Washington. 4 winter passes to go over in the middle of the winter. So In that situation every bit of additional traction would be helpful as long as the car steers well.
Thanks,