Domestic Performance has been working out a great deal with Borla and can offer a header deal for the people who are interested. This initially will not be cheap. but the first southern Cali connection I can find who wants them I will set up with an at cost deal.
You know to be honest I have no idea what the gains are going to be I just have access to two companies who build exhausts. One even does titanium exhausts worldwide. A little expensive for most of the people on this site but its available. Oh I also do titanium drop springs for the fanatic. Once again really only an option for the "big guns".
hmmmmm. Well ported stock manifolds on a series 1 don’t "do nothing" but the porting does very little compared to the series 2 exhaust manifolds. this is because the manifolds are already great. The rear (closest to the firewall) manifold is the least responsive to porting but can be polished while you have it out. You do need to take them out no matter what you do... heat coating or wrapping. Actually the coating will heat up the internal temp on the headers, which is (I have been told) better. Actually this will also improve emissions for the California owner. Personally the best solution is a well-built header.
Domestic Performance does coatings cheaper than “other” companies with or without a port or polish.
Porting the front exhaust manifold ported on the Series II will outflow any of the tubular designs, both Series I and II. We have proved this on a flowbench. But yes if you coat the manifolds, they retains the heat internally better and the hotter gaes are, the faster they move through the system and allows the headers to keep burning guel in the exhaust system before reaching the tailpipe.