I haven't found much use on mechanical things except for the impact wrench. I based my purchase on a new Crasftsman gun using the Ingersoll-Rand 231 model as, well, a role model.

You need forward and reverse, of course. Occasionally, I have used the 0-4 power control setting. Not much else to say about it. Prety straight forward: Spin off/ Spin on. No need to get facny or super-powerful. (What will you do with a 600 foot-pound capacity gun that a 250 won't turn for you?) Weight is a slight issue, as is compact size. I would not buy a $400 Snap On gun just to have the "best" of all these features together in one gun, though.

You'll need impact sockets and extensions. Get both metric, and SAE, if you have older domestic cars. I have only standard depth, not deep-well. If you can get deep-well cheaply, one or two sockets might be useful, like when spinning loose strut top nuts. Typical sets include 10mm-24mm A 27mm is also good if you are doing the crank pully bolt on pre-B230 engines

Buy a bottle of air tool oil and use it. My gun gets used mostly for lug nuts (yes, ON as well as off. Remember the power settings?) And for capliper bolts.
The rare occasion of a strut or rear bushing change.

Thought about buying an air rachet, but why? You'll find it's more a hassle to contend with the noise of the compressor and the twisted hose than to turn a rachet by hand just to gain a little speed in your work.

Body work is a different thing. A D/A sander is nice. Chisel or air saw, maybe. But I stick with electricity for my dual-action polishing.

Paint guns are big air *volume* users. The HVLP moreso than the conventional ones. Get tips in the 1.2-1.4mm range for good paint work.

Of course get a tire inflator long extansion, not the stupid bubble type thing. And an OSHA-approved 30 psi blow gun. Doubt you'll find one of these, so just set your regulator to 30 psi. And some quick couplers (male and female fittings)

Remember to depressurize and drain the air tank after each use.
--
"Can't understand why people abort Volvos, either"