The BMW M135i and M140i may appear the same, but underneath the shared appearance are two wildly different platforms. BMW changed the car’s underpinnings, moving from a rear-wheel-drive layout to one that primarily powers the front, though all-wheel-drive is available.

There was also a change in the number of cylinders – the new 1 Series downsizing from an inline-six mill to a turbocharged four-cylinder. But how do the changes translate to track? A new YouTube video from the Leaseloco YouTube channel pits the two against one another to see which is the performance king.

The 2020 M135i xDrive boasts a turbocharged 2.0-litre four-cylinder engine that makes 306 bhp (228 kilowatts) and 332 pound-feet (450 Newton-metres) of torque. Compare that to the 2019 M140i and its 3.0-litre straight-six engine that produces 335 bhp (250 kW) and 369 lb-ft (500 Nm) of torque. The M135i has one advantage – all-wheel drive. This gives the newer BMW a bit of an edge over the older rear-wheel-drive 2019 M140i. However, the 2019 model is a bit lighter than the 2020 one.

The first race has the AWD M135i getting an early lead, though the more powerful M140i quickly closes the gap before pulling ahead, crossing the finish line in 13.6 seconds. The M135i is only a smidge behind, clocking a 13.61-second time. Next is a rolling race with a 50-mph (80-kph) start. Here, the older M140i pulls away, too powerful for the M135i. The final competition between the two was a brake test from 70 mph (113 kph) to zero, which the lighter M140i won with ease.

Gallery: 2019 BMW M135i xDrive

While the M135i is the successor to the previous generation's M140i, the two do have real-world differences. The changes made to the 2020 BMW 1 Series were critical to the automaker making the right car for the segment, even if that meant changing the powertrain layout.