Not sure how the guy above knows the specs of the box but audio enthusiasts like to wank on about how good thier **** is because it meets certain specs on paper.
Everyones ear is different and everyone has different tastes.
Take the old wine analogy as a perfect example. Some will swear buy the $600 bottle but in a blind test pick the $8 bottle as the favorite.
Not knowing the specs or volume of the subs or box, it will be pretty safe to assume they will pump hard being feed the max wrms.
Pioneer are not stupid and wouldn't market such subs in a box that doesnt sound good.
If you want to spend $2000 on subs then you will get much better quality sound that hits each octave but its like my mum compairing a hyundi i30 to amg e63. The i30 does everything she needs (gets to work and back) and is cheap. While the amg e63 does it a liitle bit better (in her eyes) its no where near the price tag. $20,000 vs 230,000.
She thinks this is just a stupid price to pay, when she can get a near enough to same result with the i30.
To answer your question, look for an amp that will put out the rms rating of the subwoofers. Eg the first response seems to know the wrms rating for these subs, so look for an amp that has the combined rating.
You should be able to pick up a half decent amp that will power these subs adequately for around $150 in oz or less then $100 if you buy from over seas. I recomend you buy from oz and support the local market some.
I dont know a hell of a lot about car audio and I wont pretend to but unless your entering sound comps for spl or sq then dont get caught upin the hype of quality you want su s that go boom any of these amps will do the job. Theres heaps out there that will do it better but price vs boom, these will be enough.
800 RMS Amp: Car Amplifiers | eBay