here is the email I got from powerbass
Chad,
This amp will accept 4 gauge, and it is recommended. I’d put a 100 amp ANL fuse at the battery, within 12”. The sub amp portion is class AB, so is 2-ohm stable. At 4-ohm, the amp is 75 x 4 and 250 x1. at 2-ohm, the amp is 150 x 4 and 500 x1. You can run each channel at different impedance, if you need to. Meaning, you can run the fronts at 2 ohm, the rear at 4 ohm and the sub at 2 ohm, or even left and right at 2 or 4 ohm.
Jay Kent
Technical Director
Powerbass USA, Inc.
p. 909.993.5399
f. 909.993.5393