I added a 2 gal expansion tank and also flexible braided stainless lines to the output side. Made the pump very quiet without any changes to the mounting of it, 99% of the noise was the vibration in the hard PEX lines. The pump fittings are 1/2" NPT, common home center size.
The expansion tank is nice because the pump doesn't run every time you open a faucet, nor does it cycle repeatedly. When it comes on it's rebuilding pressure in the expansion tank and will run for a minute or more.
Note that I added a valve to bypass the expansion tank when winterizing.

