I doubt the amp is overheating only because the fuse on my power wire is only a 20A, a crappy maxi fuse, maybe that's the culprit? Because it doesn't shut the amp off or show any sign of the amp being the problem.
The amp is 1ohm stereo stable, and it can be bridged with a second amp for 1800 watts rms, here's the model: Kenwood KAC-9104D Mono subwoofer amplifier 900 watts RMS x 1 at 2 ohms at Crutchfield.com
It just doesn't seem like it would be the amp because it seems like a solid build, I would think that 900 watts (max rms, enoug to overheat the amp) would be pulling more than 20A, maybe more like 50ish? And that would make the fuse blow long before.
Once I get the new wire (if it turns out to be "4 gauge" like, 8 gauge with thick insulation, then I'll just run two wires) I'll set the gain properly and just use the bass boost on my HU is I really want more punch, I'll keep it off at the amp.