Spy shots of the 2023 BMW M4 CSL: the hardcore M4 coupe is on its way out

BMW's current M4 coupe (and M3 sedan) was introduced just over a year ago, but hotter versions are now being tested.

The M4 currently comes in base and competition grades. According to sources, the prototype shown here is most likely for the latest CSL, although it was previously thought to be for the next grade, the CS. A modern M4 CSL is not unexpected, as former BMW M division boss Frank van Meer has also stated that a new CSL model will be available in 2017.

If you are not familiar with the CSL badge, it stands for "Coupe Sport Lightweight." The last BMW to adopt this designation was the E46-generation M3, and only 1,400 CSL cars were produced in limited numbers between 2002 and 2004.

The prototype shown here is fitted with elements similar to those found on the CSL. The front is fitted with an extended lip spoiler that appears to have adjustable elements. This is joined by a ducktail-style rear spoiler and what appears to be an improved rear diffuser.

Also not to be missed are new grille inserts and a new design for the front mask's lower intakes. The prototype also appears to have carbon ceramic brake rotors.

The cabin appears to have been stripped of all but the bare essentials to save weight. A fixed roll cage option may be available to buyers.

Many modifications were likely borrowed from the new M4 GT3 racing car, including tuning the M4's 3.0-liter twin-turbo engine. The race car produces 590 hp, compared to 473 hp for the standard M4 and 503 hp for the M4 Competition.

With the latest M4 (and M3), BMW also offers an all-wheel drive option for the first time. This setup relies on a transfer case that splits torque between the front and rear axles. In addition, a rear differential splits torque to the rear wheels. This system will most likely be standard on the M4 CSL along with the 8-speed automatic, but a rear-wheel drive setup is also possible, given the car's more hardcore positioning.

The new M4 CSL could debut as a 2023 or 2024 model. Stay tuned.