We ordered a seat lift kit from LMI Welding so that we could get the seat lifted 1.5 inches to accommodate a bigger box installation so that we can get deeper bass inside of the 2500HD Truck.
The seat lift kit was made by LMI Welding and are available at link below.

https://lmiwelding.com/shop/index.php

The box installed was built by Sound Off Audio Enclosures, you can check out the box I had built at this link below.

https://www.soundoffaudio.com/ported-...