I only use Chicago Pneumatic for air tools, and I used my 3/8-inch driveimpact for most of the plugs, except for two which were stuck in there good. Had to switch to my 1/2-inch drive impact wrench with 800lb-ft of torque to bust those suckers loose. All turned out good. I'll be replacing my spark plugs every 100,000km from now on.
Work - 2003 Ram 1500 5.7 Hemi
Play - 2004 F-150 5.4 Triton