I'm looking at this from a standpoint of you don't have these aftermarket parts to begin with. You are not going to send that much more, considering you want to buy these components. A Hytech exhaust, which I was told by John to be near stock DB levels, is a twin loop design in 2.5" ID form costs about $650. This is about $200 more than any other, but this isn't a 60" clog like the rest and isn't going to sounnd like a weedeater. Mate this with a $250 Kami 3" collector header and cat and you've got a nice setup under $1000. Like I said before, a muffler shop can resolve the weird fitment for next to nothing. I can link you to some used Kami headers, if you want to save a few more bucks and are looking for function over retail cost.
The big question is: "is it really worth it?"How thoroughly one can evacuate the cylinder, the quicker it can be filled will afresh mixture. The dyno doesn't fib; it makes more power. I was told by John @ Hytech that the average gain his SC customers gain with his systems at 8PSI is nearly 20 whp. That's going to be slightly over 250 whp on my setup, if I see gains like this. This is almost free power, considering the engine isn't going to be working any harder than it already is. What will I see on the dyno? I can't say just yet.
I don't know what your expetations are, but you might as well get the best components for you system to get the best output. If you ask me, I wouldn't chnage the stock stuff if I didn't plan on getting the components that will give me the best bang for the buck. Would you rather spend $1,100 on the Comptech stuff and have like-stock gains or spend another $100 or so and actually gain power?