....like garfa stated - budget will determine this plus whether they are SVC or DVC.
The are a range of options across the board from every Manufacturer
To give you a general idea....
...take the Rockoford T3002 ($450 odd) rated 300 RMS ..actual.... 838 RMS
....or you could go a Pro Series HD5001 mono black 500 RMS for about $350
again the choose is limitless, but really depends on budget and if you wish to upgrade later.
Just make sure if you are wiring down to 1 ohm that they Amp is stable with the 1 ohm load.