The ceramic coating - inside and out - helps preserve the headers but more importantly also controls under hood heat. I have a set of 14 YO 1 7/8" TTI's on an E with B engine and Ed heads. On mine, the collectors show some rust starting and the tubes are fine. I keep running them. They fit as advertised with no adjustment. I have driven the car X country including across the desert and run >20 minutes of back to back hot laps on a road course w/o under hood heat issues. For that alone, I think the ceramic coating is worth it.