I am not aware of variations in the coatings. To me they are "ceramic" coating.
I had my headers done by Connecticut Coatings in New Haven. That was 10 years ago and still no isses.
I did not do a before and after temperature test so I cannot confirm or deny there is a containment of exhaust temps. I can tell you that I have burned myself several times by touching the headers when hot. There is no change in look to them so I get suckered in.
By comparison I have a set of JBA long tube headers on my 68 GT350 that are "factory" coated. There is a difference in appearance with them from new in that now they look dull like factory milled stainless steel.
I can not tell you that they are coated inside of the tubes like the Pantera headers are.
CT Coatings has a method of dipping the headers to remove rust without blasting them. They tumble them when done to give them a polished look.
Mine came out great. They also have different color options available such as satin black, blue and titanium. They claim that the black water spots but I don't know that as a fact.
The Pantera headers were about $450 to do in silver and the turn around was about a week. They have a web page and will accept them shipped in and will ship them back to you.
They also do other industrial coatings for equipment and buildings so they don't just do headers.
I also had them do the intake mainifold and valve covers on my 93 SHO Taurus. Those came out nice also.
Cobra Automotive uses and recommends them so I would suggest that you have nothing to loose by inquiring with them.