TTI vs Dougs

I know that there are countless threads about this, but I have a question that I haven't been able to find an answer to yet.

Both TTI and Doug's offer a ceramic coating option, but TTI also has the option for a "thermal barrier" coating to be applied to the inside of the headers. Supposedly this thermal barrier creates better airflow through the headers, as well as reducing the overall underhood temp.

Just curious if anyone has used both of these products, and has noticed any worthwhile improvement/benefits with the "thermal barrier" version of the TTI's.

I would just buy the TTI's and forget about it, if it weren't for the fact that TTI says that their 340 headers won't work on a 318. I have a 318 now, but will likely be swapping to a 340 at some point, and really don't want to have to buy a second set of expensive headers.


Gabe