Both cars are dual-motor, all-wheel-drive. According to carwow, the BMW i4 M50 has 536 bhp (400 kW) of power and 795 Nm of torque, but its weight is 2,215 kg. The Tesla Model 3 Performance has 483 bhp (360 kW) and 660 Nm, but it's significantly lighter - about 1,847 kg.
On paper, it should be an easy win for Tesla, as the 0-60 mph time is 3.1 seconds, compared to 3.7 seconds for the BMW i4 M50. However, the reality is different.
In the first race (watch from 2:58), the BMW i4 M50 won easily right from the start, but it was due to not properly launching the Tesla.
In the second drag race (4:03), the Tesla Model 3 Performance was quicker in the beginning - no surprise here - but as we can see, after several seconds, at around 100+ mph the M50 was in the lead. Ultimately, the M50 won the quarter-mile drag race with a time of 11.9 seconds, compared to 12.0 seconds in the case of Tesla.
In the case of the rolling start, at 30 mph and 50 mph, Tesla was initially quicker (quite substantially at 30 mph), but the higher the speed, the BMW M50 gains an advantage and catches up. The conclusion is that the BMW i4 M50 is accelerating quicker at higher speeds.
In the braking test, weight played a major role, and the Tesla Model 3 Performance won, substantially over the BMW i4 M50 (no numbers were provided, though).