2005 Chevrolet Tahoe LS 4WD 4dr SUV (5.3L 8cyl 4A)
With aftermarket Michelin Pilots (18 inch), I average 19-20 mpg. This is partly attributable to fuel efficiencies that GM developed over time. I try to tell as many people as possible, since I think the perception is that big SUVs get 10 or less. This is my second Tahoe - I traded in a 2004.
A 5300 engine in a 2WD - it was difficult to find, but worth it.
Only the speakers in the "base" model. Surely GM can do better! Nothing other than that.