If you used the Quatre Gain Cell on an 8ohm load - you're likely to not see any issues. It didn't like going lower that 4 ohms.
I tried one fairly recently - and on air suspension speakers (I didn't have anything ported to try it) it still sounds awesome. I mean awesome. Like a big fat Krell amp in the bottom. A good amp overall, but if you're looking for a subwoofer amp and you're looking at a nominal 8 ohm load - use it. I'm sure you'll be impressed.
I remember back in the day someone bringing in an ancient AR3a. And the bass with the Gain Cell was staggering. I was marketing director of the company, and I would tell people with Dahlquist DQ 10's - instead of getting a subwoofer, try this amp first. It was miles beyond anything at the time. And the different was not subtle.
