Just got my MBRP installed last night. Sounds SO MUCH better, glad to hear you are still liking it after a few months. Couldn't really get into the throttle when I finished since it was the middle of the night and the houses in my neighborhood are close together but excited to take it for a drive today.
If you are able to post a before/after video of how it sounds that would be great. I have been trying to decide between the MBRP and the Borla but don't want to spend the GM Accessories price.
Based on what is in the owner's manual: When the truck is running, it looks like the lockout feature only works if the lock button is pressed on the driver door. If the truck was off it will unlock the door if a key fob is detected.
When I picked mine up at the end of April, the dealer had me sign paperwork that said Q3 for the heated steering wheel and Q4 for the parking sensors.
Hopefully you get yours soon