I don't know all the specs but I believe its around a 50% load and somewhere in the neighborhood of 4-5min a tire. That's 0-40psi on a 32in tire. It's a heavy duty ARB compressor. Many rock crawlers use it.
ARB came with 2 different style bolts and a mounting bracket. I just measured and drilled holes in the fender well. Turned out good, also you have just enough wire to mount in where I did and get to the battery.
Been having issues with my rear taillight leaking because of the new 12awg wire I used to run my lights.
Made a change and used a grommet.
Now I have to get the water out of my light, I'm thinking about just putting it in the sunlight to bake.
Went ahead and added a ARB air compressor...
No benefit at all, just looks cool, makes people wonder where you got them and if they were stock. ;)
Here is my writeup on how I did it.
http://www.toyota-4runner.org/showthread.php?t=87646