I had 2 12in polk DBs and a PA 880 for over a year full bass boost max gain never had a single problem sounded amazing.
I wanted to buy some heart stoppers so I got a zx1500.1 and 2 phoenix gold elite12ds rated at 1600rms peak 3000
I blew the driver side sub first in a day and had it replaced for free. Right before it went it was literately taking my breath away and moving my hair. They were ones off the show room floor so they didn't really need to much breaking in. I had it on half gain and half bass boost I understand bass boost is bad. But these things can take a beating... well at least I thought.
Im using a line converter from rear Harmon/Kardon subs that came stock with my bmw my battery is fine and my alternator is 120amps no dimming and my capacitor seems to read ok.
I right now have the gain at half or maybe a little more no bassboost at 70-80hz and they feel so week but they move and wobble when I watch them. Just sound weak in the car.