4.8 RST Exhuast

Pretty sure this is the right area to post this question. Regarding future ls swap in my truck. I've searched all over this site and web. Has anyone owned or been underneath one of the 4.8 Silverado or Sierra RST 5 speed to know what the exhaust set up is? I know they run shorty style headers by JBA but from there back I have no clue. Really enjoyed sound of one I heard in person. Anyone know their configuration, pipe size, muffler style? This would be going on an LS powerplant in a standard 92C1500 RCSB.

I did find on another forum that they are using JBA shorty headers, Y piped into 3" , into a single in dual out muffler with 2.5" tail pipes. With Cats. I would assume they do, as they are off the floor models. Still wondering though what style/design muffler they use, or what manufacturer would be close. Really like the burble this exhaust system has.

Mines an 08 with a 5.3 auto no headers and it has a 3in y into a single in dual out 22 in magnaflow 3 in 2 2 1/2 out