Just bought this unit. I have a question for any of you current users/owners. The unit has a set of five vents directly above the tubes on top of the unit. The vents would at first blush appear to be for the purpose of releasing heat. However, the manual does not mention them. I'm concerned because I would like to put another rack item (a rack tuner) above the SVP Pro in my current rack. This would completely cover up the vents. Does anyone know if these vents need to be left open? thanks for the info!!