I experienced something similar after the installation of no-hop bars, but I couldnt pinpoint it as being the bars because it was also a new rear end.. It very well could be though, because it changes the geometry of the rear end..I beleive they relocate the center of gravity which also changes pinion angle.. Im sure more people will reply, this could be a good one..
one last thing, the vibration is at high speed, not all the time and is extra bad when turning at high speed..
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Mike Reeh
Gold #34
San Diego, CA