Don't know what you mean by 'rubber' couplings. I've been using sections of straight auto radiator hose to isolate the pump and filter and they've been in place for maybe 6 years? Not sure. They are on the pressure side too and are holding up just fine. Suction side should be easy. Just be sure the couplings won't collapse under a vacuum and inspect them after a few months to see if the chemicals are attacking the material. The advantages are quieter operation and reduced stress on the pipes and joints as they can move a little.
Al