[GNEsmond]

Your original pipes are 2-1/4".
On my first exhaust I bumped it up to 2.5" and
ran it from the flange north of the resonator on back.

I recommend 2.5 in and a double 2.5 out to either 3.5" tips or 4".
I had both. prefer the 4".

I really need your help. I have a 2006 g6 gt sedan with a 3.5L, I was hoping you could tell me the exact size for a cherry bomb on my car. i think I saw you had better recommendations about mufflers. So if you have ones that you think are better, could you send me a link to the exact one, or tell me the exact dimension. Thank you