I've only done one mild mod - taken a box cutter to the removable cover in the front bumper. I didn't want to have to deal with removing it when stuck in the mud and I'm not yet ready to buy and install the front skid plate that comes with the recovery eye access.
What came with my Towing Pack
- All Terrain Progress Control (ATPC)
- Terrain Response 2
- Configurable Terrain Response
- Advanced Tow Assist
- Tow Hitch Receiver
Additionally, I could not order the towing pack without the Air Suspension Pack:
- Electronic Air Suspension
- Adaptive Dynamics
So while crawling around under the truck, I spotted an odd flange on the steering knuckle that presumably helps deflect air towards the brakes. I seems to me something prone to deflecting rocks, mud and snow into the brakes and wheels - especially when off-roading. I'm inclined to remove it, but...