First Drive: BMW X4

IT’S an equation that will be familiar to X6 owners. You pay extra – about $9K – for a BMW X4 compared with the X3 from which it derives its underpinnings, you lose rear headroom and cargo capacity, and gain sportiness and style … of sorts.

Unlike the original X6, however, the X4 sensibly arrives as a five-seater (the X6 from 2007-11 seated four, for exclusivity), and when you look at the sportier mid-size SUV’s coupe compromises, it only sacrifices 8-16mm of headroom and 50L of cargo volume.

Sure, the X4’s swooping roofline is lower – by 36mm – but so are its seats, by 20mm up front and 28mm in the back, which brings a sportier seating position, says BMW. Rear headroom is unexpectedly okay.

The headliner of a four-strong X4 line-up is the xDrive35i, which is powered by the brand’s venerable 225kW 3.0-litre twin-scroll turbo-petrol six.

The 28i variant found in the X3 range isn’t offered, but elsewhere they go variant for variant – from the $69,430 entry-level xDrive20i to the $73,400 20d and $83,900 30d.

Given the model’s style and performance focus, the M-kitted 35i might be the obvious choice, but the torquey and thrifty 20d and the 30d – near 35i-quick and far more economical – are the pragmatist’s picks.

It takes a deliberate exploratory mission to venture into the rev range of the 3.0-litre turbo-diesel in the 30d because, with 560Nm available at 1500rpm, revs are rarely a necessity. The soundtrack is unremarkably diesel-like, but goes unheard given effective sound-deadening and the fact the mill does much of its work at little over idle.

The big oiler uses about 30 percent less fuel than the petrol flagship – 8.3L/100km on the combined cycle versus 5.9L/100km for the 35i – yet its 5.8-second 0-100km/h time is just 0.3sec slower.

The 30d misses out on the 35i’s 20-inch alloys and M suspension, though all variants get adaptive dampers. The diesel rides better, yet still has a distinct personality split between its Comfort and Sport modes, which apply their effects to the accelerator and (excellent) eight-speed auto as well as the dampers.

You can shift the X4 yourself via snappy standard paddles, but there’s little point given how good a job it does left to its own devices with all that torque.

Standard variable-ratio steering wraps relaxed highway cruise ability with the sharpened responses needed to negotiate switchbacks.

With lock on, the snout points quickly and precisely, delivering trustworthy grip. Unloading the tail brings a noticeable tightening of line, but no drama. This is a well-balanced chassis that handles nothing like most SUVs.

If, while making a passion-fuelled beeline across the BMW showroom from an X3 to the raunchier-looking X4, you experience a bout of rational thinking, it’s the 30d rather than the more obvious 35i you would choose. It says plenty about the rapid, efficient turbo-diesel six that if you stuck with your heart, the result probably wouldn’t be any different.

Plus: Packaging not as compromised as you might expect; extra equipment helps justify price premium over X3
Minus: Pricier and less practical than its sibling; marriage of coupe roofline and SUV body won’t appeal to everyone

Model: BMW X4 xDrive30d
Engine: 2993cc in-line 6, dohc, 24v, turbo-diesel
Max power: 190kW @ 4000rpm
Max torque: 560Nm @ 1500-3000rpm
Transmission: 8-speed auto
Weight: 1820kg
0-100km/h: 5.8sec (claimed)
Economy: 5.9L/100km
Price: $83,900
On sale: Now