Seriously man, check all the amp grounds. Sounds like one big nasty ground loop. My friends blazer was doing the EXACT same thing. Killed two $350+ headunits, a powerbass xa3000d, and a kicker 650.4.
Please try grounding the amps straight to the battery before more money goes into the fire pit.
I am about to order a 1500.1d MBQ, do you think I should just **** it up and buy the 2000.1? Is it pretty efficient? I would only keep the gains around 1500 because I don't have that strong of an electrical system. What you think?
Kevin