I have one Pioneer DVC 4 ohm subwoofer TS-W259D4 (350 watt RMS / 1200 watt max), with a Stealth 2.8 2-channel AMP (2 x 400 watt / 800 watt max), which is stable at 2 ohms.
I bought these two thinking they were compatible, but it's been a while since I bought them and haven't gotten round to...