For a luxury car, smoothness and effortlessness are key and the electrified 7 Series offers both.

BMW’s latest crop of plug-in hybrid vehicles has produced some of the best such vehicles currently on the market. At one end of the range we have excellent smaller cars, like the new 330e, while at the top of the range BMW offers the opulent 745e, which has the same powertrain also found in the X5 45e.

That means it has the same 111 horsepower electric motor encased in the eight-speed automatic gearbox, but instead of the 3 Series’ four-cylinder engine, the 7 Series has a much stronger six-cylinder under its hood. And according to Tom Voelk, its smooth nature and effortlessness are a perfect match for the the 7 Series relaxed character.

He says this 45e powertrain is a great fit for BMW’s flagship sedan and not necessarily because of its green credentials. Even if it doesn’t achieve its claimed all-electric range of 50 km (31 miles), thanks to its 12 kWh on-board battery pack it still manages to provide somewhere around 20 km (12 miles) of gas-free driving.

But let’s face it, nobody will buy this car to be green and save fuel or even shout about the fact that it’s a PHEV. Just like all its other plug-in hybrid model, this 745e only offers subtle hints that it’s electrified.

The reason its buyers will undeniably be interested in its powertrain is the performance it has on offer. With a combined output of 389 horsepower, a claimed sprint time to 100 km/h (62 mph) of 5.2 seconds and an electronically limited top speed of 250 km/h (155 mph), it’s certainly no slouch, and between the straight-six’s smoothness and enjoyable soundtrack, you really won’t miss a V8.

So if you’re looking to buy a large electrified sedan costing over $100,000, the 745e seems to make a great case for itself, as long as you can live with the facelifted model’s ridiculously large twin-kidney grille.