I recently overhauled my system. I'm using the following:
2 - Kicker SX650.4
Sub is undecided. I have an Illusion ND-12, but in the completely wrong box, so I won't comment on it.
First off the Kicker amps. Very cool, TONS of processing. These are probably the best amps I've seen for running an active system. The fact that each channel is bandpassable with a WIDE range of frequencies and adjustable slopes is a lifesaver. As with most Kicker, they're putting out substantially more power than rated. The birthsheets that came with them show them at a little over 100x4 @ 4 ohms. I'm a firm believer in "a watt is a watt" so I can't hear much of a sonic difference than some of the other amps I've used (JL 300/4, Hifonics Olympus XI, Xtant A4004, Orion 8004, Orion XTR800.4). They definitely stay cool, after a solid hour of playtime at high volume neither amp was over 95 degrees including the amp bridged to my sub. The fan noise is minimal even though they're in the cab with me. They stay cool enought that the fans in them haven't kicked on durning normal play. They do spool up when the amps first kick on. The monitoring features are also very nice for keeping tabs on voltage, tempature etc. The max/min voltage is also nice to see how you're electrical system is resonding under hard draw. Overall, I think these are great amps from a great company and would recommend them over just about anything for anyone wanting to run an active setup. EDIT: I just went over a few of the MANY different features and was basically a tip of the iceberg type review. If you want to know more, feel free to PM me with any questions you have.