Aux video for OEM GM Nav HU

Hi all, I think I posted this in the wrong section previously so I am reposting here. I got a visit from the guy at VCommand today and he had a product that looked really interesting. It is an interface for GM head units with the built-in navigation screen that allows you to turn the head unit screen into a monitor for your DVD or rear camera input. It is a complete plug and play as far as hooking it up. Just unplug the harness and install their harness and interface box. The cost was under $100. It sounds too good to be true. Has anyone used this before? He claims he sells tons of these but I really don't wanna take a chance on hooking it up and frying an expensive OEM head unit or having it fail a few months down the road. Up until now the only place I heard that could modify your head unit to play video charged something like $1200 to do it and it involved sending it in. Any input on this would be greatly appreciated. Thanks. Alex

this is the first time i have heard about one for gm!!!if it works then that will be great.

Well I should get one in this week. I'll post how it goes. Thanks. Alex