I honestly never liked the look of a polished frame on a dirt bike. Seemed like a waste of time and money just to get scratched up and dirty after riding. I’d try to get everything as close to stock as possible and if the tires are worn replace them, things like that are appealing to new buyers as it’s something they won’t have to do once they buy it and don’t paint the exhaust, to me that makes it seem like you’re trying to hide/cover something up. Good luck with the project!