it is 1500wrms but it is an overrated amp. it will put out about 1000wrms to 1200wrms. that would be perfect for those subs. the subs can handle 500wrms each so the amp would power it with a little headroom, which is good.
it's not over-rated. I'm looking at the manual. It's rated at 1100w rms at 14.4v, and being a well regulated amp it's probably 1000w or more down to 12v. Solid amps.