As you may know the C6 Z06's mufflers have a electronic controlled dampers that at lower engine load has the dampers closes to increase backpressure so exhaust properly flows out

Some people are removing the D/C power fuse whuch then leaves the dampers in the full open position causing less backpressure

Ist image shows the fuel trims of left and right heads.
We see they are balanced from one another and trims fairly adjusted.

2nd image is with the muffler dampers held open and you see right off an imbalance left/right and at one engine load being lean and just above or below that engine load going rich at lower engine loads.
This says with stock exhaust manifold design GM knows what they are doing and best is to leave dampers functional

Here is a compare of 2 C6 Z06s, one stock that PCM auto opens and closes the damper in mufflers and another with the fuse for damper pulled
As seen the lower graph of the Z06 with fuse pulled is the fuel trims ( LTFTS) greatly imbalanced to each other.
This is due to no backpressure and not allowing both heads to move the exhaust at the same volume

We tested what the difference in sound level in DbA of this muffler design that is now used for all C6s.

Measured what the sound level was at idle with the muffler damper open and closed as to DbA level by the muffler tips and inside the car with and without the windows open.
The C6 Z06 did have a stock exhaust system

1 foot away from muffler tips, sound level recording tool was at a 45 % angle from the tips

With damper closed 84 DbA
With damper open 94 DbA

Inside, around drivers area

With windows closed, damper closed 67 DbA
With windows closed, damper open 71 DbA

Windows open, damper closed 71 DbA
Windows open, damper open 84 DbA