With ‘efficiency’ proliferating throughout the automotive industry, even into motorsports, we could one day see a seriously fuel-efficient version of the BMW M5. Until then, the closest thing is the fuel-frugal BMW 535d M Sport turbo-diesel.

The BMW 5 Series is BMW’s second-largest, second-most luxurious model in the company’s passenger-car lineup – behind the 7 Series. The 535d is the second-most expensive model in the 5-er range, only topped by the 550i. It features an award-winning (International Engine of the Year Awards) 3.0-litre TwinPower (twin-scroll) turbo-diesel straight six engine.

Producing a class-leading 220kW of power and a hefty 600Nm of torque, the engine is the most important element to this car; the reason why BMW puts it ahead of the 535i petrol, in terms of trim level. It’s got enormous torque yet the average fuel consumption rating sits at an extremely low 6.1L/100km.

Torque is the stuff that pulls you up hills effortlessly, and with the 535d, that 600Nm pulls it from 0-100km/h in just 5.7 seconds. Compared with perhaps Australia’s most brutal mainstream V8, the Ford FPV GT sedan, the big Beemer offers 25Nm more than the V8 Coyote (575Nm). Although the Aussie V8 is capable sprinting from 0-100km/h in just under 5.0 seconds, it consumes an average of 13.7/100km.

Our test car is fitted with the M Sport package (a $4900 option) which includes a subtle bodykit, brushed aluminium accents, such as ‘M’ sill plates on all four doors, and a leather ‘M’ steering wheel. It also includes a sports suspension package and nice 18-inch alloy wheels. The particular car we tested is optioned up even further than that.

It also features BMW’s Adaptive Drive ($7000) with Dynamic Drive and Dynamic Damper Control, which replaces the M Sport sports suspension.

The Dynamic Driving Control system offers four different driving settings; COMFORT, NORMAL, SPORT and SPORT+, all of which put the steering, suspension and accelerator response into respective driving styles. The highest SPORT+ mode is the most athletic. It sets the suspension at its stiffest level, puts the steering into its most responsive and sharpest setting, and slackens off the stability control program. Meanwhile, the COMFORT mode does the exact opposite.

The car also includes Integral Active Steering, which is a complex four-wheel steering system. At speeds under 60km/h, the rear wheels turn in the opposite direction to the front wheels. At speeds over 80km/h however, the rear wheels turn in the same direction as the front, crabbing the vehicle around long bends with impeccably reassuring stability.

On this particular model, the M 18-inch wheels have been shelved for a set of 19-inch M wheels, another $3300 option. All up these extras add $15,200 onto the $134,440 price tag (recommended retail price including these options is $149,640, excluding on-road costs).

So, can you actually feel these systems and ‘dynamic’ extras actually doing anything out on the road? In short, indeed. You certainly can.

In Comfort mode, the adaptive suspension swallows speed humps and raised undulations like they don’t exist. Concave road connections and potholes are equally smooth and almost nothing is felt through the seats, however, a thudding sound is sent through to the cabin as the large 19-inch wheels drop into the recess. None of this ever gives off the impression that the car isn’t confident though.

Like almost all BMWs, the 535d does feel heavy. At 1750kg, it’s actually quite light in comparison with its rivals though; the equivalent Mercedes-Benz E 350 CDI (1825kg), and even the Holden Commodore Belina LPG (1789kg) and Ford Falcon G6 E-Gas (1786kg) are considerably heavier. It’s this overweight feel that provides a high sense of security, as if nothing will unsettle the car.

And almost nothing does unsettle it. Through a twisty mountain road, the big 535d leaps from corner to corner like a much smaller vehicle. This is helped by the adaptive steering which becomes more responsive and eager as you drive in these conditions.

This is when the SPORT+ mode is called for. As soon as you flick one of the paddle shifters behind the wheel, this mode is automatically engaged. From there, it’s transformed into a properly rapid sports sedan. The suspension goes very firm, almost too firm for city driving, and the accelerator requires little push to get the car really shifting. The steering is also weighted up and is very sharp.

The relentless torque of the engine simply irons out any element which would normally slow a car down. It pulls the car like a plane and it revs up exactly like a petrol engine. It yells and roars just the same, you could easily fool someone into thinking it’s a petrol model.

If I had one criticism to driving the 535d in this performance mode though, it’s the front end. In its effort to absorb and bend corners back into a straight road, the suspension counters any body roll in an almost numbing way. There’s moments there when optimum steering feedback isn’t sent back through to the driver and you aren’t exactly sure what the front tyres are doing. At no point was there understeer but if there was, I fear it would have been difficult to predict. Perhaps it’s the weight of the diesel engine, but it just, just misses that spark and flare that BMWs are renowned for.

Another thing you should be aware of is the stability and traction control. There’s a button to turn it off, but in reality it’s never completely off. It will come back on automatically if it thinks you’ve over-stepped the mark.

It doesn’t cancel all the fun. Hard acceleration off the mark will easily spin the wheels in a skittish, scrambling getaway like an excited dog on floorboards. The eight-speed gearbox does a wonderful job of spreading all that torque out too, it’s almost like it’s in the perfect gear all the time, no matter what position you’re putting the car in – pulling away half-way up a steep hill, overtaking on the highway with a full car – the engine and gearbox combination has absolutely no remorse for things that try to hold it back.

The 535d isn’t meant to be a seriously-focused sports car but it certainly lends itself that way, more than any other car in its class. However, it does do a great job of being a luxury car. Inside, it’s all business class. It features swathes of leather, covering almost every major fixture, including the seats, door trims, centre console, steering wheel and gear-level boot. The 535d driver is also bombarded with electronic gizmos, buttons and adjustments. Literally, bombarded.

It took me a few hours to push, adjust and turn my way through all of the interior gadgets. There’s so many options to fiddle with in this car. If you don’t like technology, the interior should be taken with two Panadol as a pre-medicated measure to cancel out the eventual headache you’ll accumulate during the familiarisation process. If you love technology on the other hand, taking a seat in the 535d will feel like you’ve just died and gone to hi-tech heaven.

The first piece of technology you’ll notice is the 10.2-inch high-resolution multifunction LCD screen. This is home to BMW’s infamous iDrive system that controls everything from the radio station to the suspension and handling settings. It’s also home to the comprehensive parking assistance programs which show views of five external cameras – including a seemingly impossible bird’s eye view and two front corner views.

All of them work a treat and make it very difficult to miss objects while reversing. The rest of the iDrive functionality simply takes time. You need to sit in the car and go through all of the menus to get used to it. As mentioned, if you like computers, this process can be fun. Once you have it under control, the system is easy to navigate using one hand and while on the go.

The Mercedes-Benz E 350 CDI is this car’s main rival. It’s around $1000 cheaper but it delivers less power and torque (170kW/540Nm). If your priority is sheer comfort, the big Benz may be the way to go. If you’re after a large luxury sedan with equal levels of comfort and performance, the BMW 535d is hard to beat.

The Beemer features iPod/USB/Bluetooth connectivity, keyless entry and keyless push-button start/stop, electronic driver and passenger seats, all the safety equipment you’d expect in a $100K-plus car, as well as five-star ANCAP safety, smart looks and superior levels of quality inside and out. And best of all, you don’t need to make many stops at the petrol station. We easily got 760km from a tank. The trip computer wouldn’t go lower than 8.4L/100km, but we were driving it predominately in traffic and tight country roads.

Is it worth $150,000? Put it this way. My idea of heaven is to constantly lap the Nurburgring for eternity. This probably isn’t the car I’d pick to do that in. However, if even heaven is less than ideal, and I still had to pay for petrol, the BMW 535d M Sport is definitely the car I’d choose. Sure, the sheer volume of technology may take some getting used to, but it’s the engineering prowess and quality drive experience that will impress far beyond most owners’ expectations.