Not sure what type of racing that you came back to! Any racing today, you can pretty much do anything to the brush that you want to. You can even be very inventive and put the larger P-94 brush in a stand up or lay down brush hood. All you need to do is be creative. Removing some of the brush, be it putting a hole in it or a slot or just removing some of the sides of the brush have very good effects. You just need to experiment. "IT IS NOT ILLEGAL TO CHANGE THE BRUSH CONFIGURATION" Rule 5-1.3 in the "1FASTDUDE'S" motor manual. lol