Where each one leads
Mercedes-Benz SL-Class
- New Mercedes-Benz SL-Class cars registered in Europe in 2022 average 270 g/km of CO₂ on the WLTP test, against 278 for the Porsche 911 in 2022.
Porsche 911
- Against cars of the same year, the Porsche 911 comes out better in New York safety inspections (fails 79% less often than average) than the Mercedes-Benz SL-Class (fails 61% less often than average).
- Fewer Porsche 911 cars in the Netherlands carry an illogical odometer record (10.0% against 15.9%).
- Measured by the cars' own fuel meters, the petrol Porsche 911 uses 14.7 l/100 km on the road, the Mercedes-Benz SL-Class 17.1.
Only measures that do not depend on how many cars were sold: pass and failure rates against cars of the same age, ratings, fuel use and CO₂. How we compare
At a glance
| Mercedes-Benz SL-Class | Porsche 911 | |
|---|---|---|
| Model years in the US safety record | 1996–2013 | 1983–2026 |
| New cars registered in Europe | 21,089 (2010–2022) | 9,884 (2010–2022) |
| Licensed in the United Kingdom | 14,178 | 52,115 |
| On the road in the Netherlands | 3,368 | 22,796 |
| In traffic in Finland | 520 | 536 |
EEA new-car registrations (CC BY 4.0) · DVLA licensed vehicles (OGL v3.0) · RDW (CC0) · Traficom (CC BY 4.0) · generations: Wikidata (CC0).
Reliability and problems
| Mercedes-Benz SL-Class | Porsche 911 | |
|---|---|---|
| UK MOT first-time pass rate | — | 88% |
| … against cars of the same age | — | +33% |
| New York safety inspections failed | 0.8% | 0.3% |
| … against cars of the same year | −61% | −79% |
| Illogical odometer records (NL) | 15.9% | 10.0% |
| US owner complaints | 31 | 145 |
| Most complaints about | Service brakes, hydraulic | Engine |
| Model year with most complaints | 1998 (12) | 1995 (12) |
| US recall campaigns | 7 | 29 |
| Manufacturer service bulletins | 102 | 6,834 |
| NHTSA defect investigations | 5 | 14 |
Complaint, recall and bulletin counts grow with the number of cars sold and are not adjusted for it. UK MOT: DVSA anonymised MOT results (OGL v3.0); New York: DMV inspections; complaints, recalls, bulletins and investigations: NHTSA (public domain); odometer: RDW (CC0).
Fuel, emissions and price
| Mercedes-Benz SL-Class | Porsche 911 | |
|---|---|---|
| Official combined fuel use, Canada | — | 15.5 l/100 km (2024) |
| Real-world use in Europe, petrol | 17.1 l/100 km | 14.7 l/100 km |
| Real-world use in Europe, petrol hybrid | 12.1 l/100 km | — |
| Official CO₂ of new cars in Europe | 270 g/km | 278 g/km |
| Average power of new cars in Europe | 391 kW (524 hp) | 394 kW (528 hp) |
| Average mass in running order | 1,935 kg | 1,660 kg |
| Dutch list price when new (median) | €154,478 | €173,394 |
| Average odometer in Finland | 134,000 km | 131,000 km |
Canada: NRCan Fuel Consumption Ratings, most frugal version of the latest year (OGL Canada). Europe: EEA monitoring of new-car CO₂ and on-board fuel meters (OBFCM), CC BY 4.0. Price: RDW catalogue price (CC0). Finland: Traficom (CC BY 4.0).