i'm using a krell fpb 300cx to power the front drivers on my lfr's and a kav 205a to power the rear drivers.

the 300cx is rated down to 2ohms @ 1200w per channel, the 250a is rated down to 4 ohms @ 500w per channel.

granted, you dont need that much power... but, to Ians comment about dynamic head room i thought i'd chime in...