I've never had the opportunity to drive an X5 xDrive30i (that's German marketing-speak for the gasoline six-cylinder version), but I'd say upgrading to this diesel is a no-brainer. For about $4000 more -- a surcharge you'll likely get back in tax rebates and fuel savings -- you have a markedly more powerful, more efficient vehicle. Like all the modern diesels we've sampled from German automakers of late, this 3.0-liter has no obvious drawbacks compared with a typical gasoline engine. There's no hesitation, no smell, no cement-truck noises. All you notice is a slightly different mechanical sound.
Like the previous-generation (non-diesel) X5 that sits in my parents' driveway, this sport activity vehicle probably won't see much time off-road. But that's OK - the reason to buy the X5 is for its stellar performance on tarmac. Forget describing the steering as balanced or beautifully weighted for a vehicle of its size--most vehicles of its size have very little steering feel at all! Every time I want to find something to criticize about an X5 (an awkward third row, outdated iDrive, spongy brake pedal), I always remember that, for the most part, it drives like a car. Add a modern diesel to the mix, and there's even more to like here.
Is there really any question as to what's the best X5 powertrain to buy? My compatriot David says that choosing the xDrive35d over the xDrive30i is a no-brainer; I'd go one further and say that the diesel is preferable to the V-8-powered xDrive48i. The turbo-diesel model costs $5000 less than the V-8 model, yet it has comparable passing power, is only half a second slower from a standstill to 60 mph (at a highly respectable 6.9 seconds, according to BMW), and is EPA-rated with significantly better fuel economy (22 mpg combined versus the V-8's 16 mpg combined). As far as the only-$3700-cheaper 30i X5 goes, the 35d, thanks largely to its 200 lb-ft torque advantage, annihilates its 7.8-second sprint to 60 mph and its measly 18-mpg combined rating. In the big X5, the strengths of diesel power truly shine. It's not perfect, though: I found this engine to be noisier than most modern diesels, and off-the-line, preboosted lag is a bit annoying (but not unexpected).
The guy at Larry's Mower Shop, where I stopped to pick up chain saw chains that had been sharpened, noticed the X5 and asked about it. He seemed shocked when I told him it had a diesel. "All the German car companies now make great diesel engines," I informed him. "This thing really moves, and you'd hardly know it has a diesel."
The BMW X5 is one of BMW's two diesel-powered vehicles for sale in the U.S. We sampled the 335d sedan earlier this year and the appeal was a bit limited -- who is actually looking for a sport sedan with a diesel? But in a big, heavy SUV, the appeal is immediate. It doesn't take a genius to lay out a Microsoft Excel spreadsheet that shows the diesel X5 hits the sweet spot between performance and efficiency for those who can't fathom the thought of driving a station wagon and giving the laws of physics a nod. This is about as close as one can get to having his cake (big SUV) and eating it, too (decent fuel economy). Until we get some wagons or hatchbacks with diesel engines and all-wheel drive, SUVs are one of the only ways to combine better mpg and all-wheel-drive traction.