Is there even a product out there that keeps its shine?
Ya Chrome or polished stainless steel.
Most of the Ceramic coatings that are used by header manufacturers is thermally sprayed on at high temperatures.
The coating on my TOG'* has held up well, with no failures, over the last 4 years.
They were coated with a duller aluminum oxide.
The newer coatings can be infused with chromium oxide to improve the shine.
Unless a true metallic coating is used, it'* difficult if not impossible for a paint to last at +800 F
The paints that say they can withstand 1200 F can only do so for a short period of time, and that doesn't mean they won't change color.