I shaved my arms too. The RacerX arms are about 7.80mm thick where it joins to the bulks. The FLM arms by comparison are only 7.45mm. I didn't have to shave .35mm off the arms though. If I remember correctly, the bulks have a 8.10mm opening at the rear and a 7.80mm at the front. The gap inbetween the arms and the bulks are different though, so, I had to take off about .10mm on the inner side of the front half of the arms.

.dk