I think you'll be happy with the Arzel system... FYI, in my own home theater project I've decided to use a stand alone fan to move air from the rest of the basement space (2000 sq ft conditioned) into the theater (255 sq ft) and then a passive "return" back out of the room. I'm going to use flex duct on both with two "silencer" baffles to keep the sound from traveling out of the room via the vents. This was my primary reason for not tying directly into the rest of the HVAC system.
The contractor recomended using flexible ducting to keep noise down. I thought it was a good idea.