Just a side thought...if you are going to spend around a grand for a good set of headers then you might as well keep saving for a supercharger or turbo. Other than that BBK I hear are a good and low priced set too. Probably the lowest price set I would buy for long tubes, if I was to buy long tubes gain. You will spend just shy of 600 shipped from American Muscle for the ceramic coated BBK ones. Kooks and SLP are a very nice set just you will be spending a lot more money for them. Whatever you do just make sure you get the ones for a manual or an automatic transmission. Some companies make specific headers for our transmission. Little future information: if you have a manual transmission needing a clutch change later on, one of the long tubes (or both) will have to be removed to do it.
Easiest way to install them is to either remove the k member, or drop or hoist the engine from the car - if you have that capability. Be sure you do not want to go turbo before you do this. Those long tubes will be a waste of money down the road. Good luck in your project.
2001 Mustang GT Hellion Turbo 5-Speed Convertible
Triple Black tastefully done with Steeda, Saleen, and Corbra exterior elements.