I am very surprised at the low MPG people are getting with the 4.2SC V8. My experience is with the 4.4l and 5l NA V8 in the Discovery and 14l/100km (20MPG) was an easy figure to achieve is stop start urban travelling.

The power and torque of the 5l NA V8 is very similar to the 4.2SC V8. Also the performance is the same - so what gives. 13MPG in urban duties with a light throttle indicates the engine is not running very efficiently if that is a normal figure.

The MPG I am getting, is right on spec with manufacturers specifications, almost exactly. Urban, and Combined especially. Extra urban is lower because I don't drive as slow as 60MPH which the specs are probably based on.

Manufacturer spec: Urban 12.6MPG | Combined 17MPH | Extra Urban 21MPG

So, the engine isn't running poorly, for a car thats 10 years on and still right on the mark with MPG is quite remarkable. 2006 Range Rover Sport 4.2 s/c with Arden bodykit

If you want a fast 4x4 at that budget I'd probably be looking at the Cayenne Turbo instead to be honest.