Just shoot the heck out of and clean and oil it well and if there is a need to do something to correct and issue than do it. But I wouldn't polish the feed ramp if its not necessary. If you DO have any issue, get SIG involved. Their CS is great.
The trigger in my SIG 1911 was a bit gritty brand new but after a few hundred rounds and some proper maintenance it's super smooth now. I wouldn't change a thing on my SIG other than adding some ambi controls like a thumb safety and/or mag release. The SIG magazines are great so no need to go aftermarket for those. You got a great deal on a great pistol!!