I turn wrenches for a living, and I don't have a lot of experience with C-H or Napa air tools.
I would highly recommend shopping from Harbor Freight, getting either a Chicago Pneumatic (not Central Pneumatic) or Ingersoll Rand impact wrench.
I have a CP-749 1/2" drive impact that I really like. It has a LOT more smoke than the Snap On guns the other guys use. It cost me $160, where Snap On runs $350+. My latest purchase is a Ingersoll Rand 2112(?) 3/8 drive composite impact wrench. It has 260 ft.lbs. of power in reverse and 240 max in forward. It will snap off 3/8" bolts with ease. It is REALLY fast and VERY light--something like 2 lbs.
I realize these both may be a little more money than you might wish to spend, but I feel they are both well worth the money, especially at Harbor Freight's prices.
