Most BMW cars possess a tuning potential that you can bring out by a relatively simple ECU remap. In this video, two BMW M cars upgraded purely by software means race each other on a 402-meter drag strip.
The footage opens on a comparison between the quarter-mile times of a stock M4 xDrive Competition and its upgraded version. Once tuned, the Bavarian coupe manages to complete the run in 10 seconds 826 milliseconds, beating its own pre-upgrade result by 0.479 seconds.
By around four minutes in, a similarly tuned M5 joins the race. In addition to an engine upgrade, it features new air intakes and exhaust system. Watch the rest to see just how intense the fight was.