Despite a decade of battering from anti-car-ists, the BMW X5, the original badass SUV, is still proudly being churned out of the firm's factory in Spartanburg, North Carolina. By June, one million cars will have rolled out from its doors.This is the new version, though after days of gawping, we still can't spot the difference between this and the one it replaces. BMW says there's a new bumper and repositioned foglights, but you'd have to park old-and-new beside each other to be absolutely sure. One thing that's certainly different is the new xDrive40d, the most-powerful diesel engine in the range (don't be fooled by the ‘40' - it's a 3.0-litre straight-six). Despite the confusing code, BMW is once again demonstrating the art of increasing power while reducing exhaust nasties - the 40d has more power and torque (306bhp, 442lb ft) than the 35d it replaces, but emits less CO2 and delivers better mpg.It also comes with a new eight-speed 'box. It's a great combination, and all those gears mean the straight-six diesel stays in its torquey sweet spot for more of the time. It also means a 0-62mph time of 6.6secs. With stats like that, it's hard to see why anyone would go for the new petrol xDrive50i - a 5.0-litre V8 that replaces the 48i.The ‘x', as with other Beemers, means four-wheel drive. We know the X5 can handle some off-road drama, but won't beat a Discovery up a slippery slope. To test whether or not this version works as well as the old (it uses the same 4x4 system), we drove to the Florida Everglades and into an alligator swamp. It turned out to be worryingly deep, but as the water lapped at the doors and a prehistoric resident licked its lips, the diffs dragged us up the other side. It might not trouble the Landie, but it's more than good enough to handle what most people will throw at it. And as for other stuff like ride and handling, BMW hasn't significantly changed anything oily, so this new car feels as good as the old one. It might not be the most ballsy face-lift ever (what do designers do at times like this?), but too much fiddling and big cars like this can turn ugly - just look at the new Cayenne. At least the boffins have been busier, and that excellent new diesel/gearbox combo is just enough to keep the X5 at the top of its game. But why mess too much? They've sold a million for a reason.