When BMW revealed the refreshed 5 Series at the end of May, we were only half occupied with the new form, the rest of our attention trying to imagine what the refreshed M5 would look like. When the M5 took its bow, we kept almost all our focus at the front of the class, save for the persistent whisper, "How much further will the M5 CS go?" BMW Blog has begun to answer that question, claiming the lighter, harder, limited-edition trim is expected to show before the year is out, boasting something like 641 horsepower and up to 590 pound-feet of torque. With ample headroom left in the 4.4-liter twin-turbo V8 — a mere tune from Noelle Performance gets the engine to a warrantied 800 hp — we're told the extra 24 horses in the M5 CS come from software tweaks and better cooling.
Some corners have made noises about a more compact 4.4-liter twin-turbo V8 that's amenable to electrification and will go into a BMW soon, possibly this one. Battery assistance strikes us as going against the CS ethos, but we'll know soon enough.
Functional revisions will have more substantial effects on the driving experience. Spy shots captured on German roads and at the Nürburgring since last year reveal a revised front intake with a new front splitter, larger rear spoiler in the mold of that attached to the M2, M3, and M4 CS models, and new diffuser. Suspension programming will definitely stiffen up, while programming for the limited-slip differential should loosen up the tail. A carbon fiber hood and revised carbon fiber roof could shed more weight above the center of gravity, and if BMW goes all the way through the CS how-to guide, lightweight seats and door panels aren't out of the question, dressed in scads of Alcantara and just enough leather to make the correct impression.
A host of CS badges will be on display, too, and we should note that — also according to BMW Blog — the initials don't stand for Coupe Sport, as we recently thought. Nor do they "mean" Competition Sport. They stand for Club Sport. It is "CSL" that stands for Coupe Sport Leightbau (Lightweight).
Almost certainly a limited-edition model, it's possible the M5 CS will strut with special colors and wheels. Spy photographers have also spotted a matte paint job, and a lusty set of gold wheels hiding a performance braking system with red calipers on at least one prototype.