I have decided that since I don't plan to race this car or intend to go around looking for ricers or Fords to beat, I will not be investing in a set of headers.

However, I AM going to do "little" things to bump up the performance and the sound of my '97 Z (of which I'm glad to be back on the road again!).

I really do like the idea of duals using stock manifolds. I've read that cats provide beneficial backpressure for the engine and have decided to keep them on, BUT may opt for a high flow/low restriction cat if the cost is OK.

Which brings me to this question. Will a true dual 2-1/2" with stock manifold and either stock or high flow CAT-and performance bullet style mufflers/resonators provide much added HP to the wheels? Will I even notice an improvement in performance other than deeper & louder sound? How about compared against a really good CAT-BACK system like Magnaflow, SLP, etc.

I will protect the fuel lines from the added pipe, and will dump out at the rear of the car. There's a real good exhaust shop in town who doesn't charge too much so this may be a good route to go.
Thanks!!