Well, anyone surprised at that?
Do as Indy suggests............the rubber may be too hard like so many are..........also, look at your top set of three pic. Note the difference in distance between the side bumper on stock and the Napa part, the big airspace on the Napa. If you are talking vibration in drive on ATX, the space should be close, I think some deadening occurs as the top rocker arm pivots slightly sideways in drive to contact that side bumper. Way too much distance there, probably doesn't touch as it should in drive.
Quick test..........sink your thumbnail into the rubber on the stock and replacement part, every replacement I've seen that wasn't Ford part was much harder than the stock rubber was even with stock rubber hard and dead.