Do you have a nice 40 S&W? I ask since 40 S&W seems to still be available more frequently that 9mm at the moment and that gun was designed to shoot it and does so quite well.
If it were my gun I would:
- Drop in a new SIG factory 40 S&W barrel (they're available fairly inexpensive and quality is very very good and your 357 gun is meant to do that swap from the factory)
- Install Factory SRT (inexpensive, easy to do yourself and the new sear will smooth things up quite a bit)
- Install a Grayguns adjustable trigger (not needed, but the adjustment they provide is nice)
- Ship out the slide to have it milled for an RMR (if that's what you want) and don't have them refinish it
- Leave the factory grips alone (or replace if they're super dinged up) or go E2 if you have small hands
- Have it refinished by CCR (Cummings Custom Refinishing). CCR's finishes are excellent and they're really the best at doing SIG's anodized frames. Have the black parts done in "House Black."
It would be fairly inexpensive if you hunt around and source the barrel and SRT kit for cheap (I bet you could find both for under $150).
But that's just me