what performance mods are worth it? [4.6L V8]
As much as I hate to say it...headers. Getting rid of those restrictive manifolds for some headers will give you the absolute largest hp gain per dollar. I would also advance your timing a little. don't get a chip for it yet. wait til you are going to bolt on all the parts that you could want on the engine...and then have a chip custom burned for you. this will give you the most out of the computer.