Just get some monkeys with Dremel tools and hammers to pound away on your gun, the results will be the same.
While Sig makes a reasonably good gun, I've found their custom shop results to be average at best. They either don't care, are too busy, or some combination of the two.
I sent my P220 away for a Labor Day special (SRT, night sights, barrel re-crown, polishing feed ramp, etc.) and got back some halfass job of an unevenly polished feed ramp, broken trigger return spring, and crooked sights.
The Sig made a return trip for repair of springs, which they managed to achieve without screwing anything else up, but I eventually replaced the barrel because I couldn't bear to look at the terrible uneven hack-job they did to the feed ramp. They claimed the appearance was "normal."
Save your money. Keep your Sig as it is, or get a better gun if your'e unhappy with it.
Grayguns is a much better Sig gunsmithy if you want any custom work done, btw. They're not as fast, but they actually care about returning you a working gun that is better than what you sent them.