5,000 mile review: This vehicle is about compromise: V8 performance and SUV comfort with less pollution and up to 30 mpg highway. But there's no mistaking that this is a diesel. You can hear the clatter at low RPM. BMW designed the X5 model with a loud exhaust note, mistakenly thinking that buyers equate noise with performance. Add the diesel's louder, gravelly engine note to the already loud X5 exhaust note and you get a noisy driving experience. It quiets down at highway speeds, but the exhaust noise is constant, intrusive, and can be annoying. In the first 5,000 miles, mpg was 24.5 mixed and 29.5 highway. Not bad for a vehicle that weighs over 2.5 tons and isn't broken in yet. This might be a good choice if you are willing to trade drive-train refinement for the comfort of an SUV that gets great mpg and pollutes less.
Solid build quality, great performance, comfortable seats, great mpg. The diesel "feels" solid and as fast as the V8. It's an excellent highway cruiser.