When BMW announced the launch of the M4 GTS we knew this was going to be a drastically upgraded version of the stock car. However, that also meant – to some degree – that the potential for further upgrades would be cut back, a theory that proved to be false. Yes, the S55 engine was pushed a bit further but the engineers made sure that reliability and the tuning potential wouldn’t be affected too much.

Case in point, the BMW M4 GTS shown in the video below. The owner decided to upgrade it ever so slightly and replaced the stock mid pipes on his car, for a better sound and maybe some HP increase. However, our good man didn’t expect the results he got. According to a video posted online and screenshots of the results, the car put down no less than 490 HP at the wheels.


It should be mentioned that all of this was done using 91 octane fuel, but even so, with some 10% transmission loss taken into account, the total engine output would reach close to 540 HP. Chip in the 502 WTQ figure (680 Nm) and you get a car that weighs under 1.5 tons and has more torque and almost the same amount of power as the BMW F10 M5.

Thanks to the water injection system, the engine is also going to work flawlessly, even if the owner also decides to increase turbo pressure. The engineers came up with this ingenious solution to prevent knock and make sure the S55 3-liter straight six engine won’t have reliability issues. Using a fine spray of water, the temperature in the intake plenum is lowered for maximum efficiency. This feature will probably be introduced on more models later on, be it M versions or not.