Depends on what you want in your system. If you're the extreme basshead type, go with a proven SPL woofer, like a DD9x1x. Do you like tighter bass, lower bass, etc...what are your prefs? If you want it to sound good, but still get plenty loud, go with Infinity Perfects, with 600 watts apiece, or Alpine Type R's with the same wattage. The Type R's are cheaper than the perfects, have the same SQ, and get a bit louder. Ask Q's and i'll try to answer as best i can.