I got one with the ultra compressor. At first I was going to get the light duty, then I started think of air tools. That lead to buying the ultra (you know bigger is better?). I still haven't finished installing it. I didn't realize when I bought it the the mounts I'd seen that hang off the master cylinder would be too small to handle the ultra compressor. So I mounted compressor in the rear in my Tuffy Security box. I've mounted the air tank behind the stock bumper but if I ever replace the bumper, I'll have to move it. So I'll move it when it warms up. I'm going to mount it inside the Tuffy box as well and finish wiring it up. As for the mount I can't use for the compressor, that will be a great place to mount a train horn. I've also got a set of switches and an extra valve so I will be able to drain it by pushing a button.
In hind sight, I should have bought a little smaller compressor so I could have mounted it under the hood. If I ever need air tools on the trail, I'll be way over my head. As for the tank, I've seen mounts that go behind the radiator for a 1.5 or 2 gal tank. There is a company that makes a mount for a 2.5 gal vair tank and evap canister but I think you have to have a lift.
I hope this helps.