I am not sure how they will handle 2 ohms bridged but the Benchmark AHB2 is a tiny amp. You would need to get two of them and bridge them mono to get 300 watts. The QSC PLX1802 is a 300 watt/ch into 8 ohm tiny AB amp with a switching power supply. It will do 700 watts/ch into 2 ohms. It is a commercial amp and has a fan for extended high power use. For home use just go in and unplug the fan. QSC makes much more powerful versions if you have money to burn. I am sure there have to be some small class D amps that will do the job.
Mike
Mike