I tend to disagree, Is there the right air flow to run the gun, no. Is there enough to get the lugnuts off, yes. I run a 1" drive off mine and it does work, just not the way it works on "shop air". Also, the air line that runs the impact is the most important. EVERY impact is rated at a certain CFM. If you cannot supply that number, you are not getting full torque. I have not seen it mentioned yet so I will throw this out there, some of the guys use what is called an "air pig". That is a smaller air line feeding a portable air tank and there is a larger hose from that tank to the gun. It will get you more air flow, but not longer run time.
Just my thoughts on this.