I got them from a guy that one of my friends has dealt with on other stuff. I know that he also sells through ebag so I can get you the info if you want. For sure you can use them with headers! And they arent car specific other than choosing the length you want. I know I spent more than what I would have on other brands like Patriots, but these have aluminized tubes so that you dont see black through the covers and are "supposed" to hold up better to tarnishing and rust.