When BMW unleashed the first X5 more than 10 years ago, it was hard to imagine anything smaller than a 4-litre V8 under its massive bonnet.
But with turbo technology having matured so much in the last decade, it is actually harder today for corporate captains to convince the board that they need a big-bore V8.
Having driven two 3-litre inline-6 X5's back to back, I am more convinced than ever that an eight-cylinder is becoming sheer indulgence for a car like the X5.
An SUV is not the ideal platform to showcase the traits of a V8. The creamy delivery and bassy burble of such a power plant are somewhat lost in such a vehicle. It is a bit like how the delicateness of a wine reduction will be lost in a chilli crab dish.
An inline-6, however, suits the X5. Especially when the engine in question is from BMW, which has perfected the configuration.
The petrol-driven xDrive35i, for instance, displays such a high level of finesse that you would easily mistake it for a V8.
It loses out to the xDrive50i in brute force and hard performance numbers, but in very little else. While the 4.4-litre V8 packs 650Nm of torque, its maximum shove is attained between 2,000 and 4,500rpm. The 3-litre xDrive35i has at its disposal 400Nm from 1,200 to 5,000rpm.
Hence its deficit is really quite minimal from a driveability point of view - if you are behind the wheel of the turbodiesel xDrive30d, I would wager very few people will even notice it.
Sure, the xDrive50i hits 100kmh in 5 seconds, while the xDrive35i and xDrive30d clock 6.5 and 6.9 seconds respectively. But this difference is not obvious in day-to-day driving. And 6.9 is still very quick.
In fact, it is the xDrive30d - the slowest century sprinter - that comes across as being noticeably more sprightly than the xDrive35i. And if memory serves, it is as effortless as the xDrive50i in most situations.
Which is saying a lot, since the two other X5's are far from sluggish.
As mentioned in earlier reviews, a diesel engine and an SUV make a sensible pairing. In the case of the xDrive30d, it is also a sensational pairing.
The 2,993cc 560Nm turbodiesel works exceptionally well with the BMW's eight-speed autobox to offer synaptic throttle response, seamless transitions and linear, dependable acceleration.
In short, it is a wonderful car at the wheel, betraying none of the stodginess and hesitancy associated with vehicles of its heft and size.