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