Well, I'm not getting a 4 stroke yet i found a flying horse for a decent price that'll probably be my last. I got seven to eight hundred miles off a cheap kit i found on ebay and it was my first motor kit so i'm hoping i have better luck with this one. The rubber between the motor mounts are actually used handlebar grips that really aren't that thick. I wanted the longevity on that bike frame and i'm up to my forth motor now and all my bearings are holding together well. Also the motor mounts are fasten with better bolts so the rubber grips don't allow movement or play in the mounting of the motors and keeps some vibration down from my small mirrors just enough for me to make proper judgement out of them. I will consider that though and try a test with and without when I get my next kit. I saved all my good bolts for it aswell.