Got fed up with the flaky finish on the black exhaust tips so decided to refinish them. Upon close inspection it seems the stock coating is very thin and was flaking on the inner lip. There were also some stonechips on the outside. Rubbed the bottom lip and inside down with brake cleaner, wire wool and some blue roll. Masked up and painted with DEI hi temp coating which I've had good results with back in my Subaru days. Touched up the outside surface with Hycote Satin black touch up brush, not a perfect match but can only see a difference up close. For anyone who wants to tidy up their exhaust I can recommend doing it, I am pleased with the results.