You will not even be thinking vibration while riding your S40 it is just not a real concern, at least not on my '06 model. Power is strong if you need it and easy and controlable if you don't. If excess vibration does occur, I doubt it will be under 70mph. I have been over 60 and my concern was with the wind on my body, not vibration. I don't see how anyone could complain about vibration on one of these bikes. Carburation and maybe some oil condsmption are about the only issues that deserve any consideration. Also possibly the cam chain and it's related parts. Oh yeah, dont forget the hard to get to spark plug....Dan