My 305 eventually developed issues with the battery connection after about 2 years of use. So I used some foam tape on the stem to limit vibration. I also went though a few mounts (breaking the tab on the quick release.) One day while riding, my 305 had been wiggling around for a few weeks, I thought the cable ties were not snugged up enough, then I noticed out of the corner of my eye the head unit falling off and hitting the ground straight under the wheel of the rider following me. The 305 was rendered useless. Turns out that I had one of the cable ties mis-threaded through the mount and after a month or two the single one let go on the rough road.

I now have a 705 mounted snugly without the foam and no vibration problems. I hear the mount for the 500 is better.