Question?

[Sweets]

Recently purchased 2004 FLHTCUI in great condition with 3800 miles. previous owner installed Rinehart true duals and said he had a experienced buddy download map to calibrate. Everything else is stock. He was not too knowledgeable about what product was used but there is no piggy back component to be found so it must be a SERT download. Bike seems very responsive and runs and sounds good. Noticed pipes were starting to get that slight golden color in rear exhaust though, maybe running lean (Are Rineharts prone to this?).
Called him and asked for the SERT kit he purchased because it's useless to him at this point and he's trying to find it.
My question is, if he can't find what are my options if I need to adjust or install the original pipes which I have as well.
Do I need to purchase a SERT kit from Harley or are there better choices. I have a Power commander for my other FAT Boy which I understand and have tweaked, but SERT are different from my research on this and other sites.
Would a new set of pipes with an O2 sensor and a Master tune be the way to go.
I'm looking for peach of mind, Bike runs great now but it's barely broken in as far as I'm concerned and spring has yet to show it's face in the Northeast. Summer riding is far different as I'm sure the Bike will start to bake a bit if things are not set rite.
Any help would be appreciated.

Thanks!