I have a 990 on the way and I am a bit worried about the size of this thing and my rack. My rack is about 9" high and I see the 990 is 7.75" high. Does this thing produce a large amount of heat where I will need more ventilation? My rack is open on all sides, but the top rack sits 1.25" above it. I have my amps sitting on butcher blocks in the open. I just hope I won't have to put this thing on a block as well...