I beat a 944s on the track (Autocross) Sunday in my 325i. His best time was 79.749 seconds, my best was 76.450 seconds. There was also a 911 at the event. His best official time was 74.367. His raw time was actually 72.367, but he shorted a corner, took out a cone and got a 2 sec penalty.
My time was good enough for 2nd place in my D Stock class. The stock Bimmer did pretty good against the Porsches, and both of them were in non-stock classes, that is. they had performance mods.
According to SCCA's handicapping system, the Porsches should have an edge on the 325, but driver skill obviously is a factor.