These pictures give a little flavor for the lack of room to drill holes and install the back-plates. In the first picture the hose on the left goes to the Garmin GNS 430W and the two hoses on the right go to the ICOM 210 COM #2 radio & the GNS 327 Mode C Transponder. There is no back-plate for the ICOM 210 radio so I just positioned the cooling hose so air will shoot into the back of a slot in the radio. The Transponder does have a back-plate but it's installed inside the radio stack framing. The second picture shows the holes I had to drill to install the cooling hose, transponder antenna coaxial cable, and wires through a rib and into the radio stack frame. The third picture is an angle piece I installed to hold the cooling hose to the Grand Rapids HX EFIS...I only show this picture because it took 4.5 hours to install these two itty-bitty-bolts, This is located directly over the pilot air vent hose under a triangular shaped reinforcing bracket. There was no room to get my fingers (or a wrench) in to hold the bolts to tighten. I finally used a curved surgical forcepts to hold the bolts while laying on my back with my head sideways partially "under" the rudder pedals. I've come to the conclusion nothing worth doing is ever going to be easy.