IR ThunderGun Impact Wrenches any opinions?

IR 231 is "the standard". IIRC 450 ft/lbs.
Back i the 80s, my shop class had about a dozen of those and the CP (Chicago NOT Central Pneumatics)
The old CP was also "the standard". Can't go wrong with either.

I have a pre-TG 232 model. Same as TG but no tungsten hammer. 550-580 ft/lbs IIRC
Love it. ebay $50. (oh, and no fancy yellow rubber jacket)

My brother has the 232-TGSL and loves it. I think he paid $200 on sale a few years ago.