The tv plunger assembly in the turbo Buick trans doesn't have the hole for the part throttle detent passage. What that means is, it's less likely to downshift into another gear when you lean into the throttle. It still can, depending on the situation, but in a turbo Buick you generally have to lean into the throttle pretty hard for it to downshift into a lower gear.
I actually don't know for sure if the bq shares that with the br calibration because I've never checked. But I'm pretty sure it does. It's a small detail that's hardly worth mentioning honestly.