Autoblog and Yahoo may earn commission from links in this article.Every generation of M3 versus C63 has been close enough to start arguments. This generation is close enough to start fights. For the first time in the rivalry's history, the two cars share almost nothing philosophically. The M3 keeps a twin-turbocharged inline-six, offers a six-speed manual transmission, and can be had in rear-wheel drive. The C63 S E Performance abandoned its beloved V8 entirely, replacing it with a turbocharged four-cylinder and a rear-axle electric motor that combine for 671 hp and a weight penalty approaching 900 pounds. One car evolved. The other underwent an identity transplant. Which one made the right call depends entirely on whether you value what the spec sheet says or what the steering wheel tells you.2026 BMW M3BMWA twin-turbo six versus the world's most powerful four-cylinder plus an electric motorUnder the hood, the M3 runs the S58 twin-turbocharged 3.0-liter inline-six producing 473 hp and 406 lb.ft in base form, climbing to 503 hp in Competition xDrive trim and 543 in the limited CS. Power delivery is linear, mechanical, and deeply satisfying in a way that makes 5,000 rpm feel like a destination worth visiting. No electric assistance. No hybrid complexity. Just six cylinders, two turbochargers, and an exhaust note that has been refined over three generations of M3.Mercedes-AMG C 63 S E PERFORMANCEOn the other side of the philosophical aisle, the C63 S E Performance uses a 2.0-liter turbocharged four-cylinder making 469 hp on its own, which already makes it the most powerful series-production four-cylinder engine ever built. A rear-axle electric motor adds 201 hp in bursts of up to 10 seconds, bringing combined output to 671 hp and 752 lb.ft. Those numbers dwarf the M3 by every measure. But the electric motor's peak output is temporary. Continuous electric output is 94 hp. Once the 6.1 kWh battery depletes under hard driving, the C63 is a 4,700-pound sedan relying on a four-cylinder that sounds nothing like the V8 it replaced. Whether 671 combined horsepower compensates for the loss of eight cylinders of AMG heritage is the question that Mercedes has been trying to answer since 2023. The forums are still deliberating.Nearly 900 pounds separate themAt roughly 3,840 pounds in Competition xDrive form, the M3 is heavy by sports sedan standards but light by 2026 standards. Its weight is distributed conventionally, with the engine up front and nothing unusual sitting above the rear axle. Corner entry feels predictable. Direction changes are responsive. Body control is tight without being punishing. For a car this size and this powerful, the M3 hides its mass better than almost anything in the segment.2026 BMW M3BMWBy comparison, the C63 tips the scales at approximately 4,700 pounds, nearly 900 more than the M3 and roughly 500 more than the V8 C63 it replaced. A battery pack, electric motor, power electronics, and cooling hardware all add mass that no amount of engineering can fully disguise. Through fast corners and heavy braking zones, the weight manifests as inertia that the chassis has to manage rather than exploit. Rear-axle steering helps rotate the car at low speeds, but at the limit, the C63 feels like it is working harder than the M3 to achieve similar cornering speeds.Mercedes-AMG C 63 S E PERFORMANCEAdvertisementAdvertisementOne offers a manual transmission.For the base M3, a six-speed manual gearbox remains available with rear-wheel drive only. In 2026, that combination, a twin-turbo inline-six, three pedals, and power exclusively to the rear wheels, exists nowhere else in the performance sedan segment. It is the enthusiast configuration that every competitor has abandoned, and its continued availability is less a business decision than a philosophical statement from Munich about what an M car should offer.2026 BMW M3BMWMeanwhile, every C63 S E Performance ships with a nine-speed MCT automatic and 4MATIC+ all-wheel drive. No manual option exists, and given the hybrid system's integration with the rear-axle electric motor, adding one would require redesigning the entire drivetrain. A Drift Mode that sends power predominantly to the rear is available for buyers who want the rear-drive sensation without the commitment of buying a rear-drive car. It is a clever feature.Mercedes-AMG C 63 S E PERFORMANCEStraight-line speed versus everything elseOff the line, the C63 is marginally quicker. A combined 752 lb.ft launching through all four wheels and rear-axle steering, tightening the exit of slow corners, gives it an advantage that is measurable on a stopwatch and irrelevant on a winding road. Zero to 60 arrives in roughly 3.3 seconds. Top speed is electronically limited to 174 mph with the AMG Driver's Package. In a straight line on a prepared surface, the C63 is ferociously fast in a way that makes its four-cylinder origins feel academic.Mercedes-AMG C 63 S E PERFORMANCEEverywhere else, the M3 pulls ahead. Lighter weight, more communicative steering, better brake feel under repeated hard stops, and a chassis that rewards the driver who carries speed through a corner rather than just adding it on the straight. Multiple comparison tests have reached the same conclusion: the C63 is faster on paper, the M3 is faster in the hands of a driver who knows what to do with it. As Autoblog noted in its spec comparison, despite the power differences between these rivals, similar 0-60 times result due to weight disparity. Horsepower is a number. Weight is a feeling. And 900 extra pounds is a feeling you cannot ignore.2026 BMW M3BMWAdvertisementAdvertisementPrice and the question nobody wants to ask out loudStarting at roughly $76,000, the base M3 with a manual and rear-wheel drive is the cheapest way into this rivalry. Competition xDrive pushes to roughly $80,000. Both include three years of complimentary maintenance, a 4-year/50,000-mile basic warranty, and the S58 engine that has been bulletproof across three years of ownership data.2026 BMW M3BMWAt around $85,000 to start, the C63 S E Performance asks for $9,000 more while delivering 168 more horsepower and 900 more pounds. No complimentary maintenance is included. The question nobody wants to ask is whether the C63 would exist in this form if Mercedes had not needed to meet fleet emissions targets. That does not make it a bad car. It makes it a car built to satisfy two audiences at once, and both audiences can tell.Mercedes-AMG C 63 S E PERFORMANCEThe bottom lineIf driving enjoyment matters more than chasing numbers, the BMW M3 is the clear winner. Its characterful inline-six, sharper chassis, and nearly 900-pound weight advantage combine to create a car that feels more alive, more engaging, and more rewarding every time you get behind the wheel. The Mercedes-AMG C63 S E Performance fights back with higher horsepower, cutting-edge hybrid technology, and the bragging rights that come with 671 hp. Both are excellent machines, but the M3 is the purer driver's car.This story was originally published by Autoblog on Jun 11, 2026, where it first appeared in the Car Buying section. Add Autoblog as a Preferred Source by clicking here.