Please don't even bother to consider Ractive as a viable option--they're crap.

I personally would stick with as much stainlesspiping as possible. The reason everyone refers to the cheaper headers as "ceramic" is not because they are made out of ceramic but because they are made of lower-grade steel and have a ceramic coating to help prevent rusting.

That said, the A'PEXi World Sport is nice but one of the reasons that it provides a very mild sound is that the only thing stainless about it is the muffler itself. The pipes are all mild steel. The DC Sports exhaust is full stainless as is Comptech--which one you pick is really a matter of budget. Same deal with headers, as long as you go stainless there's not really a bad one in the bunch (except for the Ractive of course). The fact is that at most you'll see a variation of maybe 2-3 hp from each one if you're just sticking with bolt on mods.