Powering Polk Audio RTI A9's to full 500w?

I recently acquired a set of Polk Audio RTI A9's - and seeing as they're rated at up to 500w - what would you have to use to power them to 500w - most AV receivers are rated at 80-200w. I've seen amplifiers to around 250w.

What would I need to buy to get to the full 500w? On another forum a member posted this QSC - GX Amplifier - http://www.qscaudio.com/products/amps/gx/gx.htm - which doesn't seem right?

I'm asking only out of curiosity, and obviously to learn