I have the Barsto drop in barrel for my Sig P229 and I like it. I purchased the 229 40 S&W as a carry weapon and purchased the 9mm barrel for the range. It shoots the same - reduced recoil of course - and it is a lot cheaper than shooting 40 S&W.
I want to get a 9mm barrel for my G23 but money is a matter at the moment but I would not hesitate to buy one.
I'm not sure about Lone Wolf barrels but Barsto also offers match grade barrels.
If it were me and it was going to be strictly a range gun I'd go with the caliber I wanted to use.