Our laser wash doesn't have rails, no brushes and does a great job of getting the bugs off after a long HWY run. On the weekends I do my own hand wash and wax on. No swirl marks or problems with my 330 or so far in the M3. If the car is realy realy dirty, the laser wash will only get the top dirt off. Still need to do it by hand. I usually dont let the M get too dirty though.