@jayhat , I am going to second LawnDart here. He is right. I at one point thought I would do the dual battery before the ARB Dual air compressor and the air compressor came first (in the passenger firewall location on a Bandimount) and I cannot even begin to describe how useful the compressor has been (tubes for boating, air mattresses, compressed air for cleaning things off, tires, etc.)

To put it in perspective I went ahead with a solar setup and the compressor over a dual battery setup. (Dual is still on my radar) but I would NEVER move the compressor out of the engine bay. It gets hot, its loud, and i like not having to open any doors (not even the hood) to get to the air. Also the ARB dual is HEAVY, maybe too heavy for where you want to put it (unless i missed it and you wanted to go with a smaller, lighter air compressor).

I understand you are going to do what you want to do, but seriously contemplate your REAL needs and then make a decision.