FPrice, I've done this:
Bought a 1991 colt in 9mm, got a .38 Super bbl and mags for it. The ejector as issued was a little too long to easily eject loaded Super rounds when clearing the piece. So I shortened the ejector just enough to let the Supers get out. Never did need to do any extractor or breechface work, gun seems fine. The 38 super barrel I bought even seems to chamber 9x23, so I put in a heavier recoil spring and a shock buff, gave it a go with a few rounds. No apparent problems noted, but I think this barrel's a bit weird in that regard, 9x23s don't seem to drop in other Super barrels like they do mine. Just some info, hope it helps.