Not quite a mod, but I added helmet hooks to my P200. Got the idea from the guys over at stellaspeed - it is very useful. I don't have to carry my helmet around anymore! Wahoo!
I did make a stupid mistake though - it was dark and I accidently dropped the washer from the bolt into that hole. Is that a problem? Is this going to mess anything up? I tried looking down the hole to locate the washer, but it was dark and I didn't have a flashlight.