When I bought my 14 GT TrakPak it had a CAI on it with sound tube hooked up. I have twin tip GT500 mufflers on it and notice no noise from the interior and I like the sound of the GT500's a lot better than my stock mufflers.
I am going to separate the clutch and brake fluid so the clutch does not share the hot brake fluid and I will be removing the sound tube because it is just in the way.
There is a guy on Ebay selling everything for $12. I ordered it just so I have everything here at the house and don't have to drive for an hour to get to a hardware store.
2011 2014 Mustang 5 0 Sound Tube Delete Kit | eBay
To me the 5.0 in my 14 has a totally different sound than the 4.6DOHC in my 97 Cobra.