The emissions stuff in the first place doesn't hamper performance enough to make their removal worthwhile solely for that reason, so using headers that allow the emissions to remain in place doesn't hurt performance.
One thing I will say about headers. It depends on what you use the truck for, as to what is going to work best for you. My Hedman's hang down below the front spring a bit, and many that wheel their trucks say that is unacceptable, which is understandable. Me, I'll never hit, so it's not an issue. I'd hate to have you think that all of them are going to fit the same though, then buy some only to find you hate the way they fit.
My Hedman Elites are real good as far as leaks, fit, and plug access. The ball/socket setup (instead of the leak prone flat flange most use) on the elites is superior, and the flange thickness (where they mate to the head) is also very good, which helps reduce bolts backing out, etc. I'm not using locking bolts at that location, and they haven't loosened up on me.
Only plug I can't use a socket on is #5, and I can still get a regular wrench on that one.
Fit was very good, hydraulic clutch posed no issue. Had to bend them out of the way of the shackle bolts just a bit, but that's pretty minor compared to some.
One other thing to consider is rust. I would suspect that rust is going to be a major concern for you, so I'd get some opinions on what has worked back east for folks and lasted. I suspect a non-coated header is a death sentence back there.
