Michael you were dead on about grounding head unit with amp power wiring, noise is gone and stereo sounds great, I spent a fair amount of money this year buying rev8 towers, 4 XS 650 speakers and 2 JL amps. I never had this issue with my Clarion amps but new JL amps draw more power and have more output power.

Anyone having popping noise when using trim pump, easy fix is install 3 50v 100uf capacitors on blue,yellow and green leads at trim switch and then ground all three caps to main circuit board where breakers are under the dash. I stripped the insulation off the leads and sodered caps to wires then used glue gun to insulate leads at capacitors also sodered all 3 caps ground leads to ground wire. This
repair worked really well, I was worried about damage to cross over board in tower speakers as popping noise was very loud***