I definitely like the idea of reducing temps under the hood but I think there is the potential for reducing header life by wrapping them. Ideally, stainless headers would be nice to wrap since they are stronger but I don't recall the expansion factor of steel vs. SS and how that would differ to the material that is used to wrap the headers. I would think the companies making the wrap would consider that, but ??.
There is a reason why wrapping headers usually voids a warranty and maybe if someone knew how to properly wrap the headers with the correct tightness, pattern, etc they could avoid failure or at least delay it and make it worthwhile.
When change of temp, condensation etc. begins it work on the steel and weaken it, I can imagine depending on the flexibility of the material and it's expansion factor quite a bit of stress from the wrap being applied inward around the pipes. As most know, wrapping something in that fashion even a few times can apply a great deal of friction to lift 1000's of pounds. Many I know say they will never wrap their headers again and swear by it. There is plenty of evidence out there that support their claims...and pictures too. Myself, I will trust a ceramic coating on steel and there are some good ones out there...or at least they claim to be. As much as I like the idea of wrap, I'm just not sold on it....for steel anyways.
I've heard of some sprays (silicone i believe) that can help with rust condensation issues but don't know much about it.
