Performance, power and 0-100 km/h
2026 BMW M3 Competition xDrive has the quicker recorded 0-100 km/h time at 3.4 seconds, compared with 6.0 seconds for 2025 Mercedes-Benz C-Class C 300 4MATIC. 2026 BMW M3 Competition xDrive has the higher listed output at 530 hp; 2025 Mercedes-Benz C-Class C 300 4MATIC is rated at 258 hp, a difference of 272 hp. The torque figures follow 2026 BMW M3 Competition xDrive at 650 Nm and 2025 Mercedes-Benz C-Class C 300 4MATIC at 400 Nm. These figures describe straight-line potential only; they do not establish braking performance, ride quality, steering response or durability under repeated hard use.
Range, battery, charging and efficiency
2025 Mercedes-Benz C-Class C 300 4MATIC has the lower recorded consumption at 7.6 L/100km; 2026 BMW M3 Competition xDrive is listed at 10.2 L/100km. Test cycle, temperature, wheel size and charging conditions can materially affect these results, so only figures measured on the same basis should be treated as directly comparable.
Dimensions, cargo space and towing
2026 BMW M3 Competition xDrive provides the larger quoted cargo volume: 480 litres versus 455 litres, a difference of 25 litres. 2026 BMW M3 Competition xDrive is 43 mm longer overall. Exterior size is not a benefit by itself: a longer body may create useful room, but cargo shape, rear-seat space and ease of parking still require a physical inspection.
Price and overall assessment
2025 Mercedes-Benz C-Class C 300 4MATIC has the lower listed starting price at $45,400, compared with $80,900 for 2026 BMW M3 Competition xDrive. 2026 BMW M3 Competition xDrive leads in more of the shared headline fields, but that is not a universal verdict: a buyer should weight price, performance, range and utility rather than simply count category wins. The assessment is based on the specifications shown here; it is not presented as a two-car road test.