The Alpine type R subs hit very hard at 500 watts rms. They can take a little more wattage (500-600 watts each) and still perform well. I'd go with 1000 rms watt amp maybe from Alpine as well. The mrp-m1000 is a great amp. For a little more you can get the pdx-1.1000. Also get a ported box that is built custom to the subs. The box is just as important as the amp. I'm running one type r powering it with 500 watts (mrp-m500) and can be heard a block away, literally.
Check out ebay for great deals on the subs and amps.
Check out this video on youtube of the subs performing:
http://www.youtube.com/watch?v=0_xu8FrXjY0