My experience is similar.
The OEM pump could definitely be quieter, but 90% of the noise is mounting and pipes.
The plumbing is the noise maker. Adding an air chamber helps as well.
Amazon.com: SHURflo Accumulator Tank: Automotive
It is an easy mod. I replaced my "whole camper" water filter with one and never looked back. I use an inline filter on the spigot at campgrounds that use well water to remove silt.
Lou and Laura with Bella - German Short Hair Pointer
2008 GMC Sierra 2500HD Crewcab SB Allison Duramax
2010 Flagstaff 8526RLWS - Superglide 3300
HAM CALLSIGN - KC3FFW