I would like to offer a tip about those air impacts on tire changes. You had better be careful how tight you get those lug nuts. If you get a flat on the road, you might not get them loose.
Although I also use an air impact, I usually snug them up by hand. If you have ever had to change a flat tire at night on a dirt road in the rain, you will understand.
I use mine the most for taking stuff apart.
John