[radz28]

Some gears are short-shifted before redline in some gears. 1st, and 3rd (if I recall) are also limiting torque. That will likely result in the throttle not opening all the way, or perhaps, some timing being pulled, all in order to keep torque below GM's thresholds. Optimizing these settings (and more) can net probably most cars good gains, because even stock cars seem to benefit from, at least, the torque reduction regimes.

Your '19 might come with a T87a, which you can get from HPTuners, unlock for about $250, and start tuning away. I know my '20 has the T93 (and all '20s), but have read some '19 ZLEs come with T93s, too. If that's the case for you, then you'll have to go to HHP and get one of their conversions. My tuning will start this week, after I receive mine tomorrow. I'll probably have some impressions this time next week. I'm not looking to change much though.

I have been told a couple times about how the tranny tune can come from the ECM. On another car I know, we've played with the VTT and VVE and can definitely tell the transmission shifts a little differently. There are spark changes that can be adjusted, too, that can help. Those are the ones I've been playing with, but I believe there are more. We've tried to only touch the least amount as possible on the other car to be safe.

I'd recommend getting a tune for the tranny, regardless of what some other say. There ARE calibrators magnitudes smarter and more experienced, but we've seen gains from relatively good testing, from only tranny tuning, so...