I have a 2015 Z51 M7. Lots of upgrades to the car, ARH mids, Borla catless x-pipe, B & B Bullets, removed the NPP actuators and the first set of actuators, Halltech carbon CAI, Katech light weight flywheel, DSS carbon drive shaft, LG coilovers, Innovator West, light weight balancer, MGW shifter, trunnion upgrade, MSD intake manifold, Solar TB, tune and various other upgrades. The Bullets are loud at wot but otherwise not much louder then stock when cruising, little bit of drone around 1600 rpm. The biggest change I noticed was with the CAI and headers and the Solar TB regarding response time.