Let me try and help here. The 8 valve manifold only needs 1 air supply. Easiest way I could tell you how to do this is to take the good deal compressor and tank and plug all holes except 1 line to come out and Tee that line into the 1 feed line you have now from the current setup in car. Wire in another relay for the new compressor and Tee off your current signal/sense wire that goes from pressure switch in your car to the new relay signal/sense. Only need to run 1 pressure switch and this will give you more volume at same psi .I currently have a manual management with 1 480 compressor, and a 4 gal tank, I recently came across a good deal and bout 1 3 gal tank 1 480 compressor and 8 valve manifold and controller, problem is I’m not 100% how to plum it, I know I need to connect the tanks, but does the manifold just get 1 air supply? I will run the front bags off one tank and the rear off the rear tank does anyone have a diagram for this setup? Yes I searched, also how does it work with 2 tank connected? I’ll be plumbing each compressor to different tanks, but do I need 2 pressure switches? Any help appreciated.