silveradosam

Ok so i want to get a overhead computer thing put in my truck. They come in escalades and denallis. The things that tell the gasmileage and such. IF yall could post a picture from a escalade and a denali as well as the features of it like what all it will tell me. And is there a diffrence between the escalades and denalis. A local dealership told me it would be 700 for the unit alone and he didn't even know if it would work but i was told it would.