For the 740Li, BMW specs its twin turbocharged, 3.0-litre inline six-cylinder engine. The engine itself is well regarded as a very competent unit, but when it's under the hood of the 7-Series, it turns BMW's biggest sedan into something remarkable.

For one, where BMW normally puts a larger V8 engine, the 740Li uses an inline six. By being lighter (the 750Li xDrive is 204 kilograms heavier), less weight over the front axle makes the 740Li more nimble and easier to turn. Although the steering ratio is slow and most suited to the type of relaxed driving 7-Series, the quality of feedback from the steering wheel and chassis make the 740Li a car that drivers will enjoy. Excellent brakes make this sedan a well-rounded automobile.

When you're considering the purchase of a 740, you know you're getting the smallest and least powerful engine. BMW says the engine makes 315 horsepower and 332 foot pounds of torque, and it make not seem like much in a big, luxury sedan, it's reasonably adequate. The eight-speed automatic transmission gives the small six greater flexibility.

Part of the reason is that this engine makes peak torque from 1,300 to 4,500 RPM. This allows you to use a more relaxed throttle when accelerating, almost the same advantage that you'd get from a diesel engine. However, since the torque is abundant, I found that - for the first time - I could use this car's Eco Pro drivetrain settings without it detracting from the driving experience. This is a shocking revelation coming from a racing driver, I know.

The reality is that with that much torque available at such relatively low engine speed, you find that you don't often need high revs to make the needed acceleration. This translates into exceptional real-world fuel consumption for a luxury sedan. It's not a primary reason to buy a 7-Series, but it's certainly a welcome byproduct.

I subject the 740Li to a range of conditions, split between city and highway driving, with a couple of snowstorms thrown in for good measure. At the end of my test, I averaged 12.6 litres per 100 kilometres at an average speed of 47 km/h. In any other sedan of this size, I would have been lucky to average 15 l/100km in those same conditions. BMW says the 740Li xDrive is rated at 10.9 city and 7.3 highway, though I don't necessarily believe those numbers are achievable in real-world conditions.

BMW's secondary controls are becoming easier to use with each redesign and refresh. The basic climate and audio controls on the instrument panel are simple and logical, while the more complex commands are accessed through the iDrive controller. When it was introduced, iDrive was a lightning rod for criticism, it's now rather easy to use for both simple and complex commands - and it can even become second nature the more you use it. Some settings, however, remain buried deep in the menu tree.

The L in 740Li indicates that this model is the long wheelbase version, with an additional 140 millimetres (5.5 inches) behind the front seats. In Canada, only the 750i is available in short wheelbase. Rear seat passengers will find a footrest for each outboard position. There is a belt for a middle passenger, but putting three passengers in the back of this long 7 would be in bad form. The back seat is also heated with ventilation available as an option.

Unlike many cars that include a simple sport button, the 740Li's driving modes from Eco Pro through Sport+ are truly distinct and discernable from one another. It's simply up to the driver to select the 

Given the 740Li's fuel-efficient, six cylinder engine and all wheel drive, I'd suggest that its most direct competitor is Audi's A8L flagship. The Audi A8L 3.0T has a price advantage, at both its base price ($97,400), as well as similarly equipped to the BMW tester (about $108,600), but the A8L doesn't quite match the 7-Series' excellent driving dynamics.