I've ran Reeflo HH Golds and Dart Golds for years. Some rubber or neoprene under the pump and a small length of flex PVC on the inlet and outlet of the pump will go a long long way in reducing if not eliminating the resonance. I much prefer flex PVC over the rubber coupling idea in large part because of the permanent connection vs a hose clamped connection. If you don't mind the risks of the rubber connection, that will work well in isolating the pump. Just make sure you use good hose clamps and keep an eye on the rubber in case it starts to crack. While that shouldn't be an issue, it would be something that would concern me in the long run. Also, not attaching the PVC lines to the walls will also help. If you need to attach them, add some neoprene between the wall and PVC. Mouse pads are typically made of neoprene and work well for this.
