L9h 6.2 stock exhaust

[Silver62]

Well I’ve searched and can’t really find the answer I’m looking for. I have arh long tubes and catted y pipe and the stock cat-back. I’ve read that the stock cat back flows well. But i also seen a cut away of the stock muffler and it doesn’t seem like it would flow well with the necked down diameter and all the different baffles that the exhaust has to go through. So i was wondering if anyone has flow tested it against other mufflers. I really wanted to keep the stock cat back because I don’t want it really loud and don’t want to cut it up but don’t want to be leaving a lot of power on the table because of the muffler