I'm considering getting some air tools, but I really don't work on the cars too often. Maybe once every couple months at most. I guess what I'm really wanting most though is an impact to help with the axles and such. As nice to have as they would be, I don't think I really *need* ratchets. So how much would a small air setup cost with a decent impact vs an electric impact? How big of a tank would be needed to not have it be a frustration because it's too small? I just don't want to go to a local store and by the first thing and end up with cheap crap.