The rivalry between the BMW 7 Series and Mercedes-Benz S-Class is the rich-person equivalent to the BMW M3 and AMG C63 rivalry. However, these two gigantic luxury bruisers are beginning to change quite a bit. Rather than using the typically luxurious V8, both cars are beginning to get smaller, more efficient powertrains. Luxury and efficiency don’t typically go hand in hand but this is a brave new world we’re living in. So which of these two efficient luxury cars is quicker, the BMW 740e xDrive or the Mercedes-Benz S450? TFLC finds out.

In this case, the Mercedes-Benz S450, it gets a 3.0 liter twin-turbocharged V6 that makes 362 hp and 369 lb-ft of torque. That engine is mated to a nine-speed automatic and, in this case, powers all four wheels. According to Mercedes-Benz, it can get from 0-60 mph in 5.4 seconds.

In the other corner is the BMW 740e xDrive, which has an even more unusual powetrain for a luxury car. It sports a 2.0 liter turbocharged four-cylinder engine that’s mated to an electric motor. That combination makes 322 hp and 369 lb-ft and sends power through an eight-speed auto and to all four wheels. According to BMW, the 740e can shoot to 60 mph in 5.1 seconds, a quicker claimed time than the S450.

But before we see which is faster, TFLC decides to check out their rear seat luxury amenities. In the back of the S-Class, rear passengers are cossetted in a stunningly luxurious cabin. The test model in this video is equipped with such niceties as massaging seats, a refrigerator, heated and cooled cupholders, as well as a rear-seat entertainment package. Aside from this specific car’s Willy Wonka interior color scheme, the S-Class’ rear cabin is a stunning achievement.

On the flip side, the BMW 740e tested here lacked a ton of optional equipment, so its rear seat was rather spartan. In fact, in the video at least, there didn’t seem to be much more than your average 5 Series would have. It’s kind of disappointing and a bad showing for BMW. Admittedly, though, the 740e rang in at $99,000 (as-tested) while the Mercedes-Benz S450 was over $140,000 (as-tested). So the 740e could be optioned similarly to the S450, it would just cost a helluva lot more than $99k.

Finally, the drag race starts, with both hosts in the back seat, letting their drivers do the racing. In the drag race, the BMW 740e handily beats the S-Class, thanks to its significant weight advantage (all of those fancy luxuries are heavy) and its electric torque. Having said that, it seemed much nicer to be in the back seat of the S-Class during the race and, considering that these cars are more about luxury than straight-line speed, it’s probably the better luxury car. But that hybrid powertrain of the BMW 740e is mighty impressive.