Summit chambered muffler. An yes I also took off the resonator.

 

i deleted the muffler and gutted the third cat on my old 2014 single cab 5.3. was very very tame, and i really couldn't tell when it was in V4 mode unless i really concentrated.

i think im about to do it to my new 2017 crewcab 5.3

 

Thanks for the replies guys. Toes does your exhaust have a nice rumble now?