Posted for Walter Atkinson <walter@advancedpilot.com>:

 The two goals may not be compatible.  I *might* consider coating the inside
if I had a NA airplane.  Since my exhaust plumbing is under the cowl, I'm far
less interested in it's appearance than it's function.  I don't show my
airplane in Concours competition and I'm not in it for bragging rights...
other than performance, longevity and low maintenance.
 
 Yeah, it looks nice.  What does it REALLY do for me?
 
 Walter