Well, I was dead close on my guess LOL. I have lots of experience in a M6 car at the strip, just is what it is.
I bolded a section there. The problem trying to compare M6 times, is not all drivers are created equal. Those that know how to pedal the launch AND speed shift the car properly will obviously run the best. That will create a massive gap between those that get a decent launch, but don't speed shift.
For sake of definition, speed shift would be keeping the throttle buried to the floor all the way down the track and just stabbing the clutch and snatching the next gear as fast as possible. Took me a LONG time to get comfortable with that as it definitely didn't feel natural at first. Friends of mine tried all kinds of electronic gizmos to aid in this effort in their cars, but I never saw them do much better so I just learned the hard way without any electronic help.
I think the M6 ZL1 probably has a WOT shift feature built in though?
That's what it looks like and it's a lot going on. You have to not only balance on the clutch as the tree drops, and NOT roll forward in the process, you have to finesse the launch to use as much power as the track will hold without spinning the tires, wheel hopping, or bogging. Takes several warm up runs to find that sweet spot and with limited time at the track it's tricky.
I had a line lock button on the shifter ball and did my burnouts in 2nd gear. I found about 50mph to be the best speed to get the tires hot quickly, but those were race tires so YMMV on streets. Release the brake and roll forward with the tires still spinning and let them grab the track on their own as you roll forward. You'll also notice I'm checking my mirrors which were each aimed at the rear tires so I could insure both were smoking, AND I pump the brakes to insure the LSD was fully engaged. Doing a one wheel peel can burn up the LSD clutches real quick.
Then just launch as best you can and force your right foot to stay planted. I learned by starting with just a 3-4 shift as it's the easiest. Once I was comfortable there, I started doing 1-2 and 3-4, and when I had that down I went for it and added 2-3 which is obviously the most difficult. I almost never missed a shift with that method, and I mean 1 or 2 times EVER in 100s of passes. The key is shifting that 2-3 like you're 100% confident it's gonna make it. Any tentativeness and it likely won't go. Be sure to open palm that 2-3 shift, had a buddy slip off the ball in the excitement and broke his thumb when it hit the dash. Tucking your elbow in to your ribs may also help with lining up that shift.
Learning to speed shift the car lowered my ET by a bit over 3/10ths and picked up 2MPH if memory serves. It makes a huge difference.