The Mrs. & I bought an '04 Yukon XL K2500 Quad-steer.
What a beast that thing was.
It had the 6.0. Which lead us to finally have to rid ourselves of it.
Mileage when towing wasn't bad @ 8-10 but just driving around was rough on the wallet.
It's been gone for so long, that I forget the actual combined mileage but it was rough.
What was absolutely phenomenal was that Quad-steer.
When towing you guys know what it's like to make a U-Turn.
With this thing I personally could turn with a load of horses with ANY Honda civic.
Some days I really wish I had that thing back but Naw!
It was too expensive and we got rid of all our trucks & trailers after the last chick flew the nest.