What is it?
It was inevitable, really.
When BMW first set about electrifying its line-up with an extended range of plug-in hybrid models a few years back, its initial focus was very much on fuel economy and lowering CO2 emissions.
But as premium brand rivals have entered the scene with newer - and arguably better - executive car choices, the German brand has added a new and important facet to its increasingly popular petrol-electric models: performance.
Proof of this comes with the new four-wheel-drive 545e xDrive. It forms part of the recently facelifted 5 Series line-up that's due to land by the end of the year, building on the basis provided by the popular 530e, global sales of which now top 50,000.
Driven here for the first time in pre-production form, it picks up developments already seen on the larger 745e xDrive and X5 xDrive45e, most notably a six-cylinder petrol engine in place of the smaller and less refined four-cylinder unit found in the 530e.
The turbocharged 3.0-litre engine is borrowed from the 540i, where it develops 329bhp and 332lb ft. It operates in combination with the same 107bhp/196lb ft gearbox-mounted electric motor already used by the 530e, with a 12kWh lithium ion battery mounted underneath the rear seats and boot providing electrical energy.
Together, the two power sources endow the 545e xDrive with a total system output of 388bhp and 442lb ft of torque, or some 101bhp and 133lb ft more than the more fleet-friendly 530e.
It’s all sent though a standard eight-speed automatic gearbox and BMW’s rear-biased xDrive four-wheel drive system.
The result is a 1.2sec lowering of the 0-62mph time, at 4.7sec. The 2020kg 545e xDrive also receives a governed top speed of 155mph, against the 146mph of the rear-wheel-drive 530e.
The added weight brought on by the larger combustion engine and four-wheel drive means the 545e xDrive cannot match the 530e in terms of CO2 emissions and overall electric range. Still, at 38g/km and 34 miles on the WLTP cycle, it is remarkably efficient, given its strong performance slant. Top speed in electric mode, like that of the 530e, is 87mph.
The impressive efficiency is achieved, in part, through an adaptive recuperation program that uses information from the 545e xDrive’s navigation system to optimise its running over any given journey.
Underpinning its role as the more performance-oriented of BMW’s five 5 Series plug-in hybrid models, the 545e also receives staggered wheel and tyres, those up front being 245/40s and those at the rear 275/35s. Buyers get to choose between standard 17in and optional 18in or 19in rims.