some amps gets hot, some dont. regardless, ventilation is always a must, unless you have a 100% efficient amp that puts out no heat at all (impossible anyways).

I'll try to go to my friend's house and take pictures of his setup. He has almost no air space between the top of the amp and the glass. He has two fans hooked up (not too big, not too small). He's an engineer (machinist) so he can pretty much do anything with metal. SOOOoo....he drilled holes horizontally through the heatsink and viola, water-cooled system

Not the cheapest thing to do, nor the easiest, but when the amp stays cool all the time, we have a peace of mind.