i am considering this ... just how bad is the vibration?

teeth rattling? just a humm... mirror vibrating?

You just feel it in pedal and steering, its very minimal, no mirror shaking, it happen on very light load.

Im sure a tire sidewall can remove all that, but right now i can live with that no problem.

The vibration is only barely noticeable.
The benefits outweight the vibration.

You guys must have nerves of steel. I can barely tolerate the slight steering wheel buzz with the stock mounts.

I've had my hockey puck mount on for a few months now and have had no issues. I absolutely love it over the stock mount. You will tend to notice the vibration at first, but it "goes away" with time - meaning you forget about it.