What I found with ceramic coated headers on a SBC v8 I had for years, is though the shine may dull over time, the color stays the same. That might work out well for you, based on what you've shared for your goals. I'm curious to hear your results. Are they coating the inside and outside or just the inside?
FWIW yesterday I picked up my freshly re-coated Holeshot 4 into 2 system. It feels like an early Christmas present (to myself)! I had my doubts based on the condition it dropped the pieces off in, but the work appears to have been done quite professionally. The packaging alone must have taken some time! Here's a few shots of the collector, outside and in. I'm curious how they were able to clean inside so well....? The company that did the work is:
http://www.lo-ko.com/
Can't wait for riding season to return...