Subwoofer Amp Suggestions?

Looking for suggestions for a stereo subwoofer amp in the $2-5K (range new or used) to drive a pair of Kinergetics SW-800s (5 x 10" drivers- see system). The amp needs to be comfortable with a low impedence load ~3-4 ohms and will operate from 60Hz & below. The XO rolls off at 18dB. Needs to be XLR balanced inputs. I'd prefer it to weigh 80lbs or less. Class D not my thing.