The current BMW M4 coupe (and M3 sedan) only arrived on the scene a year ago but a hotter version is already out testing.

The M4 is currently available in base and Competition grades. Previously thought to be for the next rung up the ladder, the CS, the prototypes you see here are more likely to be for a modern CSL, according to sources. Former BMW M division boss Frank van Meel also said in 2017 that new CSL models were coming, so a modern M4 CSL is not unexpected.

If you’re unfamiliar with the CSL badge, it stands for “Coupe Sport Lightweight.” The last BMW to feature the designation was the E46-generation M3, with the CSL cars built in a limited run of just 1,400 units between 2002 and 2004—such tiny numbers make it an exclusive offering, and only the most dedicated opt for the extra expense and somewhat harsher and noisier ride characteristics.

The prototypes shown here are fitted with elements you'd expect to see on a CSL. The front sports an extended lip spoiler which looks to have an adjustable element. It's joined by ducktail-style rear spoiler and what appears to be a revised rear diffuser.

There's also no missing the new grille insert and new design for the lower intakes on the front fascia. It also looks like the prototypes have been fitted with carbon-ceramic brake rotors.

We suspect the cabin has been stripped of all but the bare essentials in an effort to save weight. There may even be the option of a fixed roll cage for buyers.

BMW M3 CSL (E46)

BMW M3 CSL (E46)

It's likely many of the modifications have been borrowed from the new M4 GT3 race car, including potentially the tune of the M4's 3.0-liter twin-turbocharged engine. In the race car you're looking at 590 hp, versus 473 hp in the standard M4 and 503 hp in the M4 Competition.

With the latest M4 (and M3), BMW is also offering the option of all-wheel drive for the first time. The setup relies on a transfer case to split torque between the front and rear axles. A rear differential then further splits torque between the rear wheels. It's likely this system will be standard on the M4 CSL, together with an 8-speed automatic, though a rear-wheel-drive setup is still possible, given the car's more hardcore positioning.

Look for the new M4 CSL to debut in 2023 as a 2023 or possibly 2024 model. Stay tuned.