So I checked the sub last night, it has a slightly noticable buzz at low volumes and it goes away at higher volumes and both subs check out at 4ohms. The other performs with no flaws whatsoever at all levels. With the box flipped down like it should, I couldn't hear anything wrong at all I emailed kicker tech support with the findings. I don't think there's anything that can be done since it is functioning like it should and out of warranty by 3 months.

He told me when he initially hooked it up that he ran the sub wired both ways - switching the terminals + and -. He also mentioned his friend blasting it at full power with the amp, something he didn't mention until last night. So I don't know if he fried something in doing that. That being said, I can't justify paying him back any money for the sub or replacing it after he admitted to crossing the wires and running it at the levels he did.