The QSC GX3 is rated for 425W @ 4 Ohm it can drive speakers as low as 2 ohm. It should smoke your pioneer receiver. Be aware that a pro amp is just an amp, you'll probably need some kind of pre-amp and/or processor depending on your sources, typically pro audio gear doesn't get mixed with consumer grade gear, although the GX3 does have RCA inputs and screw terminal outputs so it's not impossible to integrate into a home audio setup.
edit: There are other amps out there from Behringer, Crown, Peavey, etc that all fall in the same budget. I've read several favorable reviews of the QSC but it's probably worth doing some homework if you're serious about a pro amp, there are several other potential options.