I purchased the Sensor VSD 4.5 gpm pump to replace the original - and very noisy - ShurFlo 2.8 gpm in a Holiday Rambler Vacationer. The new pump was quiet, but provided less water pressure in both the kitchen and bathroom faucets than the old one. I returned it as being defective, and bought the somewhat cheaper Sensor VSD 3.7 gpm pump. Although much quieter than the old pump, this also produced less pressure than the original. I emailed the manufacturer regarding my problems, and after a few additional exchanges to answer their questions, I was told that the restrictors used in current faucets would cause the pump to not "read" the demand like the old pump, and therefore not provide maximum pressure. Sure enough, this was the proablem. Removing these government required restrictors at the aerators solved the problem. I am very satisfied with the product and the very good technical support by the manufacturer.