Yeah, it's not hot, but definately the warmest piece of equipment I've ever owned. I'm going to cusomtize some ventilation holes so it will hopefully dissapate a lot of that heat and help the amp last longer.
You're right, the specs on this thing indicate that at 8 ohms it will turn out 400 watts, 4 ohms 600 watts and 2 ohm 800! My only concern is something failing and the repair shop not being able to find a part, or it will cost more than the amps worth. But as of now, it's really making the 603's play VERY well.