I wrote a big check last year for a set of the top of the line TTI ceramic polished ones for my C body last year since they were one of the few that had a large primary set for a C body. They did indeed fit very well and could be installed with the engine in as well. It was tight but they can be worked in from under the car, it is amazing how tight the fit is in some places like near the torsion bar but they did fit with no "modifying" needed. I was most impressed by the coating as you said I have had ceramic coatings before and it was always "good way better then paint" but still its a header its not perfect. These TTI polished ones are INSANELY good it looks like a chrome almost ( a dull slightly chrome maybe ) and seems pretty bulletproof. I had a couple painted sets I had for other vehicles ceramic coated locally by our top place in town last year and it was MORE its was like $300 each set and they do not look near as nice as the TTI... They are expensive but you get what you pay for sometimes. I also got the full 3" system from them for the same C body and same story it fit like a glove pretty much and was top quality stuff with all the hangers, an H pipe, etc.