You got AWD so PSM is not really needed unless you want the car to cut throttle and brake for you when driving on slippery roads. In the summer I find it totally useless.

 

Ah - but not everyone may have your mad Jeremy Clarkson driving skilz..

Over on the BMW M3 forum - crash reports usually start out "So I was just driving along and turned off my DSC.. (same thing as PSM).. when out of nowhere.."