Noob needing some info

davencp33

Hello to all. I just recently purchased my 370 and have began to look at upgrades. First thing will be the exhaust. I was thinking Stillen headers and a Borla cat back. Now I'm not sure on high flow cats. I live in Indiana and here all cars have to pass an emissions test every 2 years. Does anyone have a good choice when it comes to high flow cats that will pass an emissions test? Or even a better choice on exhaust components?
I'm also thinking of a programmer but, I read on here that a tune is a better choice. OK. Imagine you're talking to someone who doesn't exactly know what a tune is. lol
I guess it would just be easier to list what I'm thinking of getting and allow someone to critique my choices. Full exhaust, programmer or tune, and eventually a supercharger.
Any feedback would be highly appreciated. Thank you.