PSM and snow

[emayer]

Actually, both answers are right!

PSM should be kept on almost all the time.  The circumstances in which it should be disabled are when starting off in deep snow/ice conditions.

Since PSM works by selectively braking a spinning wheel, you can see that in those circumstances you'll essentially be shutting things down when most needed to get bite.  Once moving, PSM should be turned back on.

Over the years, I've had the opportunity of driving several 911 variants during the winter in Germany.  With snow tires they did great except in the really deep stuff.

If pricing winter tire/wheels you may want to check with Jack Williams.  I've gotten really nice packages for even less than Tire Rack.