Is yours an automatic trans, by chance? I just put this in last night, and the vibrations are kind of unreal with my manual trans. I was expecting a modest amount, but nothing like this.
Above 2000 rpm, it is mild, and about what I would expect. Driving normally, engaging the clutch about 1000-1200 rpm from a stop, it is pretty brutal, especially on a cold start. Let it slip over 1500 rpm, and its bearable.
My rearview mirror is bouncing like I'm blasting a wall of 15" subs in a sound off competition.