exhaust question

A Nismo 1 5/8 header gained an ITS 240Z (no real headwork allowed) a smidge up top, and a fair amount of torque at the low end vs. an N42 cast iron manifold (see dyno results at Zhome.com). Interpart/BRE header gained them more like 5hp, and gave about that increase in torque throughout the useful rpm range. A 3" exhaust cost them nothing hpwise, but gained them nothing either.

Regarding JetHot coatings, I and others have had the silver stuff flake off and the headers rust. I would not recommend them, unless you use the higher temp (more $$) coating. The 1300 coating is NOT up to it. Unless they do mine again for free, I'll be using Swain or some other source for having my header coated.