That's bad ass. I'd give him $1500 for it if it wasn't all the way across the country, depending on how it looked.
However, I know my way around turbos pretty well, and 58mm tells you damn near nothing. A/R and trim with that would be pretty descript, but providing the inducer diameter only is like giving the bore of an engine, but not the stroke or number of cylinders. Doesn't help much.