Re the Harbor Freight electric impact gun...
I got enthused by reports here on the forum. I bought the 120v version figuring I could use my MH genset to power it. Tried it on my 2500HD truck as a test. No good. It loosened several nuts but not all. The ones it didn't loosen, it beat them up badly. I got the tight ones off with my 4 way wrench with a short pipe for extra leverage. That told me I had two different tools for the same job, and only needed one. I returned the gun.
Now you can say the nuts were too tight. Or I need to maintain them so they can be loosened by that gun. I decided I couldn't count on that. It's easier to just carry a breaker bar and a piece of pipe. If I was changing tires often, it would be a different story.
I'm not a strong guy, but I realize some of you are 20 years older than me, so that is a consideration. But since the HF gun wouldn't do the job, it's moot.