The header I used was a Hedman. Not too expensive, but made of iron so if you dont want it to rust, get it powder-coated. I didn't bother with a ceramic because where I live (Ontario, Canada) it gets fairly cold and I was driving the car in the winter at that time. Ceramics will crack sometimes when the header goes quickly from below freezing to operating temp (the ceramic coating and the iron underneath expand at different rates when going from cold to warm, and this can cause the coating to crack). I had a custom downpipe made at a local muffler shop (2.5") and then put an Magnaflow 2.5 in-out cat in the place where you normally find the EX cat. The reason I put it there was so if I wanted a cat back exhaust for it later on, it would bolt right up. You will need to weld in bungs for your o2 sensors and lengthen the wire for the after cat o2 sensor so it fits (you have a before and after cat sensor).
Cost: 250 for the header, 100 for the cat, 200 for labor (Canadian dollars)
Cost of a new manifold: 650 + labor (unless you get a used one, that would have been 400)
This saved me money, sounded much better and helped the engine breathe a bit better (went from a 1.5 inch downpipe to a 2.5 inch downpipe, not to mention that the original manifold pipes were about the thickness of my thumb lol)
Oh, and btw I'm usually on 7thgencivic. If you have any really technical questions, send them to Speedfoos on that site. Even tho he parted out his '03, he's one of the most knowledgeable people on the site. I'm pretty confident that I know what I'm doing, but if i get confused, I ask him