Keep us up to date.
I wonder if the ECU would need to be reset...

I've found that changing out a cat-back system does little for performance, but a tuned set of long-tube headers and a good CAI can do wonders, but may require a new ECU chip.

Ceramic coated will work as well as stainless and not discolor. Stainless, OTH, can be lighter.

Do keep us informed.