Although I do not have a ZL1, I do have a Whipple on my SS. the forced induction makes a difference with the exhaust sound. I deleted all my cats with everything stock, and like Jimabe mentions, it sounded awful, I hated it. So I did the Borla ATAK axle back with NPP (11925), mid & x pipe (60606) and swapped in their resonator (60608) in the mid pipe area. I am super pleased with it now, no drone, normal cruising you can barely hear it, moderate acceleration it growls pretty good, and it still screams pretty loud when you stand on it.
https://youtu.be/l_QUOHdkb4k
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2017 1SS M6 Hyper Blue Metallic NPP, MMR 228 Z/28 replica wheels, Front: 20 x 9, Rear 20 x 11
Stock: 416hp/427tq, 12.21 @ 116.80
Modified 02/2019: Whipple SC w/ 3.500 pulley, LT4 fueling, NW 103 TB, Roto-Fab Big Gulp, Kooks 2" jet coated, full Borla ATAK exhaust, DSS axles, Gforce driveshaft.
Tuned by EFX Tuning 688hp/632tq
Best 1/4 to date: 10.705 @ 131.92