I have a custom cat-back that ran me $225 w/ a Magnaflow muffler. The sound is ok, louder in the car than outside (if that makes sense). That is what my brother told me. I heard that since my piping is not stainless it will eventually rust.
At the time I thought a cat-back was an axel back. Yeah, I thought the resonator was the cat
So, I was like $500 for that little bit or replacement
Come to find out the cat is up by the headers
To make this short: I wish I would of went with a real cat-back.
I believe they come with like 1,000,000 mile warranty against defects and rust and $hit like that!!
You get what you pay for!!