Not sure about the tow hitch, The nevada is real leather (LEDER) and it's mentioned in your vin because is an optional upgrade! Sweet deal. Factory Vinyl is not mentioned.

Also check other forums on XOUTPOST and on eBAY for NAV systems. Most of them on ebay are from China, (because they had bought the tech from german aftermarket companies a few years back) I got a 7' navigation touchscreen with 32 gb storage and movie playback for $375 plus like $25 bucks for shipping. It was some of the best money I've spent! It's never messed up or glitched on me once. Always gets me right to my destination. Congrats on the car, I have an '06 3.0i. Enjoy your ride!