I Installed Sound Deadening Under Everything In My Silverado. Gutted The Interior. 

The roof has the biggest flat metal sections along with the inside of the outer doors, these should be priority for deadener. Also there's an egg carton type foam with an adhesive backing that can be applied to the inside of the interior panels.

Just need to swap the body control module for the heated seats. Maybe the harness depending on the seat

What you are pointing to on the floor under the drivers seat is the airbag control module. This should not be swapped unless your airbags have been deployed.

The thing under the seats is for airbags. Yellow connectors in automotive means airbags

Thing under the seat is for the airbags

Is there a big sound difference with 50 and 80 mil? I know you are running both on different trucks.

Will these stick on the back side of the front wheel wells??

6 inch lift with 20x12 on 35x12.50?

Where did you get the sound deadening

Best part is driving that sex machine 10+ min in