Bought a firebird GTA back in June. 5.7L, 350: car is full stock.

See attached pictures... yuck

First things first, i am looking to get a true dual setup, new headers and maybe a replacement cat if the old cat needs to go. Stock exhaust is NOT stainless and has been replaced in the past (previous owner). Everything is all rusty looking; no go in my book.

What i need to know is:

Can my 350 GTA even support a true dual system without scraping everywhere i go? Speed bumps, Pennsylvania road system, shitty driveways are all encountered daily. I already scrape the underside once a week just driving to/from clients houses.

Physically, is there enough room to neatly tuck a dual exhaust system under my bird or will i encounter issues finding pathways to run pipes through? Assuming I don't want to run dumps, just straight out the back like stock.

If so:

Post pics of your cars underbelly for me, I am interested to see how yours went and what parts you went with and why you chose X manufacturer over others. How much did you pay to have them installed?

How much HP gain should I expect with a new set of headers and X True Dual setup with say 2.5"? what about 3"? What about mixing 3" and 2.5"?

And whats all this physics shenanigans about backpressure when it pertains to duals? Each pipe gets 4 cylinders so does back pressure affect the exhaust differently? Is it now similar to having two 4 cylinder engines? And in general: Whats the difference between a single pipe exhaust and a dual pipe exhaust as it pertains to positive/negative pressure? (yes i've already read a few articles posted here on the matter, just want further clarification).

Finally:

Car still needs to be 100% smog and street legal, I live in the state of PA and do not have a "friendly" mechanic for inspections..yet. If you do recommend parts, take this into consideration.

 

This...

And this...

Pretty much sums up the problem. There isn't room for true duals. True duals in our application will never be 100% smog legal.

On a stock engine, the #1 benefit of an aftermarket exhaust is sound. You'll get a performance improvement, but it's not going to be anything earth shattering.

 

You will be better off with a dual cat single 3in exhaust system. Less problems down the road. It will make the same amount of hp.