BMW M is celebrating its 50th anniversary this year and we can't think of a better way to mark the occasion than the announcement of a new M4 CSL (Competition Sport Lightweight). While the M3 Competition already packs a healthy 503 horsepower, the CSL tacks on 40 more while simultaneously stripping 240 pounds from the its curb weight. BMW says this makes the 2023 BMW M4 CSL the fastest production BMW to ever lap the Nordschleife, doing so in 7:20.2.

543 horsepower is plenty impressive for a compact sport sedan, but the 240-pound diet from the already-svelte Competition model is the real eye-catcher here. The CSL weighs just 3,640 pounds. That's 20% more weight than the E46 M3 CSL (which pioneered the carbon fiber roof in production BMW M cars) had to carry around. Good thing the M4 packs 50% more power — enough to propel it from 0 to 60 mph in 3.6 seconds on its way to an electronically limited 191-mph top speed. That's actually 2/10ths slower to 60 than BMW's own figure for the M4 Competition xDrive, which checks in at 3,979 pounds. All-wheel drive counts for a lot off the line.

While the CSL gets more power, peak engine torque remains at 479 pound-feet. The CSL's forty bonus horses come from an additional 5.8 pounds of boost (for 30.5 psi total) and recalibrated engine management for higher-RPM power delivery. There's also a lightweight (go figure) titanium exhaust and a new set of firmed-up engine mounts that should improve both response and feedback. Pulling an entire American out of the M4 required somewhat extreme measures, to the point where BMW halved the amount of available seating in the name of reducing mass. In place of the rear seats, you get a handy little helmet storage cubby and accompanying cargo net.

While that's one of the M4 CSL's most obvious concession to lowering curb weight, it certainly isn't the whole story. The CSL's hood, roof and trunk lid are all carbon fiber, as are the remaining bucket seats. Those shapely thrones account for 53 of the 240 pounds BMW shaved off the Competition's curb weight. Lighter-weight and more sparingly used sound insulation saved another 33; its lighter wheels, carbon ceramic brakes and forged chassis components contributed another 46. BMW even slimmed down the grille. Think we're joking?

"The model-specific, weight-minimized BMW kidney grille has a more minimalist design than on the standard M4, with fewer slats and wide spaces between them optimizing airflow to the radiators," BMW's announcement said. "The unique grille features red contour lines and 'M4 CSL' badging."

Unfortunately for BMW, Road Test Editor Zac Palmer — Autoblog's staunchest defender of BMW's recent nose job — was too busy playing with other cool cars to speak up on behalf of BMW's design team, rendering our internal vote unanimous: it's still ugly. The carbon trunk lid looks good, at least, and BMW says the integrated spoiler generates "significant" rear-axle downforce.

The CSL sits lower than the standard M4 Competition and gets its own Adaptive M Suspension tune to account for its reduced weight. Helper springs were installed both front and rear to keep the firm primary springs in place when the suspension is in full droop, making dynamic transitions more linear and predictable. Rubber control arm mounts on the rear subframe were also replaced with ball joints to reduce compliance and improve damper response. Finishing off the CSL package is a set of Michelin Pilot Sport Cup 2 R tires in 275/35ZR19 up front and 285/30ZR20 out back

The 2023 BMW M4 CSL will sticker for $140,895 when it goes on sale later this year, but we expect real-world transaction prices will be far dumber than that. Production will begin in July and be limited to just 1,000 units. Good luck.