I reckon it is easily a substitute for the X5 4.8i, absolutely surpasses the X5 3.0si but isn't even close to the new 4.4 V8 which the X6 gets, and I presume X5 might at some point.

jcl: yeh you can definitely tell it's a diesel by it's idle sound from outside the car, and if you push it past around 4000 rpm you hear it rattle a little. but it's acceleration is very punchy and responsive. I guess as a wide generalisation I can understand that "can't tell it's a diesel" comment but yeh it is a bit of a stretch.

I'll snap a couple of pics of the torque/power graphs from the brochure later and upload them, gotta go out now and I'm late