The modern diesel vehicles available in Europe are nothing like the smoky clackety-clack things that most people in the US are familiar with. The emissions are low, the noise is tolerable, and the performance is very good. A few of the UK car magazines rated the 330d over the 330i, with the former only losing a tiny bit in terms of acceleration. The 3.0 diesel in an X5 should be an outstanding engine and it's a shame that we may never see it here.