I just had to deal with loud noise and vibration of my new 2012 A122 pump.
Since I had installed a Whisper King pump in another camper prior to this, I knew the noise and vibration from the A122 pump was excessive. I believe the pump is the Shurflo model that has been discontinued.
I changed the hard plastic pump output hose to a soft flexible rubber hose and put enough slack into it for a loop just prior to the T connect above.
I also put 1/2" rubber mat under the pump to cushion it.
The existing pump was occasionally kicking on for a couple of seconds, and I found the "pressure spring" in the pump was weakened. I stretched this out another 1/8" and tightened up on the sensitivity screw, and that took care of the intermittent kicking on. There was no leak anywhere to cause it.
I also added some foam insulation wherever the pump output pipe was making contact with a cabinet wall.
Net result is the pump is now running just about as quiet as the Whisper King that I had before in the prior camper.
However, since the pump pressure spring was weakened and "worn", I am getting a new pump to have as a replacement, just in case.
This water pump vibration seems to be a common issue, but with some work it can be dealt with. That is, if you can work in a cramped position.