Originally Posted by Vise
Except that BMW does not recommend you let the car just sit idling to warm up... its been discussed before, apparently they recommend you let it run for 30-60 seconds until the idle relaxes and then don't drive it hard until it fully warms up. It will really only warm up properly/fully when being driven so having it idle for 3-4 minutes isn't helping much aside from engine temp.
Agreed. In addition, long periods of idling when cold actually creates more engine wear than driving gingerly to speed up the warm up process.