Don't buy one of those "disposable" oil less compressors they only have a life expectancy of a few years! (Most of the genaric brands) I agree that a good craftsman is a good deal but not a cheap one. Also their is no substitution for volume unless your going to run a paint gun. I have a 5hp 60 gallon upright and it runs all the impacts great. You don't have to wait for it to fill up every couple minutes. I would also consider a two stage which most of the higher end new ones are (pumps on both strokes rather than the "up" stroke). If you spend a little more now it will keep you from spending more later. I also beleive that you get what you pay when it comes to impact wrenches. I have bought cheap no-name "500 ft-lb" guns and they sucked. I would have had better luck using it to beat on breaker bar than for it's intended use. A higher end gun is probably closer to the actual advertised power, I love my "625ft-lb" Ingersol-Rand professional, although I paid almost $500. If you do buy a bigger gun make sure you utilize the power adjusting knob when removing smaller or rusty fasteners so you don't break or strip them out.
