all you need to polish stainless is a little elbow grease and some Mothers Mag Polish. Here are some pics of my Python, Anaconda, and nickel P229 I've polished up with Mothers Mag Polish. I've barely started with the P229 though and it needs more work. After polishing I coat them with a couple coats of Gun Wax to protect the finish. It keeps the very shiny, protects the polished surfaces and makes clean up MUCH easier after a shooting. I've NEVER had any evidence of surface corrosion on any of my polished guns, especially since they are stainless.

For those wanting DIY info on polishing these may help you.
But polish at your own risk...

XDtalk the offical everything to do with polishing thread

DIY Barrel polishing write-up