Kooks or ARH worth it?
The reason why stainless is cool cause it don't rust, so it's a do it right and only do it one time issue instead of doing it like more or other times. The mild steel is pretty good but after a while it may start to rust but it will take it alot longer than other headers like pacesetters and etc. brands that are not stainless steel.
I don't know how long you keep your cars, or if you missed the part where my last set is now 12 years old and working great. Only done once and cost considerably less than my Kooks.
I'm not saying there aren't benifits to stainless, I'm just sharing my experience. You don't HAVE to buy stainless for them to work well and last a long time.
