I do not use any gaskets...make sure your flanges are perfectly flat first!
I have stainless steel TA knockoff headers that is sold by a few vendors. After a about a year and many heat cycles the flanges were not flat anymore. I went through Felpro 1400 header gaskets every few months.
I had a machine shop make them perfectly flat again. Now I just smear some high temp RTV around the exhaust ports to seal it up. No more gaskets to fail, no more leaks.
If you machine the flanges flat and then use a gasket again, you risk warping the flanges again. Thats what I've read, anyway....and if you think about it it makes sense.:smile: Just remember the factory did not use any gaskets on the stock headers.
I have heard good things about those Remflex gaskets but never got to use them.