Long tube headers are the only headers with any real gain. It is debatable whether it is worth it compared to test pipes or ART pipes. If you go with LTH's, it removes your factory cats. You can get a cat back on it if you buy a Motordyne XYZ Y pipe with the cat option. If you go that route, then you can just buy an exhaust from the midpipe back with the same diameter of the Y pipe. There aren't too many options with headers and are difficult to show quantifiable evidence on why you should. Of course I bought LTH's anyways :P
I'm having my exhaust put on as we speak, so if you wanna check it out, I'll be posting a video with untuned dyno results tonight. I just did my baseline last night as well. I have PPE LTH's, XYZ Y pipe with cat and a Tanabe exhaust. I'm crossing my fingers in hopes it sounds good. I'll have it updated here later. Hopefully the community can get some good info out of it.
LTH with HFC + CBE = ?