delloro,
It's a C4 Fab spare battery tray. I bent up the tabs that are used for the battery hold down because they ride right on that rubber boot that's on the wiring by the firewall, then painted it black.
So far, I've just done a little driveway testing (I just got it installed prior to going back to work, I'm on a 14/14 schedule offshore oil & gas industry). No hard numbers yet, but it took less than 5mins to hook up, go from 30psi (where my dealership likes to set my tires on service) to 40psi (where I like them to be), and unhook my manifold. The manifold is 3/8 tubing branching off on each side with a common block (Tee, gauge, valve, and QD fitting) in the front. I've got my air line run down to just inside the passenger side bumper corner (in that void, I haven't fab'd a mount yet for it) and use a jumper to get out to the manifold.