I'm lucky in that my impact gun has yet to meet an axle nut it couldn't remove, and it's nothing special.

On occasion, I have to borrow one of my coworker's IR Titanium 500lb-ft 1/2" drive to get out stuck trans bolts, or another's 3/4" drive Snap-On for seriously stuck crank pulley bolts (J-series V6's, specifically.)

A 3/4" drive impact gun will kick the ass of any bolt on a Honda car, too bad they're so expensive.