I would think that rubber under the seat brackets would at best remove some small vibration that might be otherwise transmitted to the seat but if the rubber was soft enough to do any real good it would allow the seat to lean left and right, fore and aft as you start stop, and turn left and right. This would be more annoying, I would think, than the vibration that was eliminated. It would be better, easier, and more useful to add padding to your upholstery.
You didn't say what size tires you have or their profile?
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RickN
White 88GT 5spd - Grey Interior
White 85GT Auto - Grey Interior
[This message has been edited by RickN (edited 07-03-2004).]