Where each one leads
Audi S3
- Against cars of the same age, the Audi S3 comes out better at its first MOT test (passes 19% more often than average) than the Mercedes-Benz C-Class (passes 1% more often than average).
- Measured by the cars' own fuel meters, the petrol Audi S3 uses 10.0 l/100 km on the road, the Mercedes-Benz C-Class 10.9.
Mercedes-Benz C-Class
- Against cars of the same year, the Mercedes-Benz C-Class comes out better in New York safety inspections (fails 38% less often than average) than the Audi S3 (fails 29% less often than average).
- Fewer Mercedes-Benz C-Class cars in the Netherlands carry an illogical odometer record (4.5% against 11.1%).
- New Mercedes-Benz C-Class cars registered in Europe in 2022 average 116 g/km of CO₂ on the WLTP test, against 183 for the Audi S3 in 2022.
Too close to call: NHTSA overall safety rating.
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
| Audi S3 | Mercedes-Benz C-Class | |
|---|---|---|
| Model years in the US safety record | 2000–2025 | 1991–2012 |
| New cars registered in Europe | 69,332 (2010–2022) | 1,573,424 (2010–2022) |
| Licensed in the United Kingdom | 36,555 | 342,811 |
| On the road in the Netherlands | 2,533 | 78,492 |
| In traffic in Finland | 513 | 49,488 |
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
| Audi S3 | Mercedes-Benz C-Class | |
|---|---|---|
| UK MOT first-time pass rate | 81% | 80% |
| … against cars of the same age | +19% | +1% |
| New York safety inspections failed | 1.2% | 1.1% |
| … against cars of the same year | −29% | −38% |
| Illogical odometer records (NL) | 11.1% | 4.5% |
| US owner complaints | 88 | 192 |
| Most complaints about | Air bags | Electrical system |
| Model year with most complaints | 2015 (53) | 1995 (49) |
| US recall campaigns | 12 | 6 |
| Manufacturer service bulletins | 4,671 | 73 |
| NHTSA defect investigations | 6 | 11 |
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).
Safety
| Audi S3 | Mercedes-Benz C-Class | |
|---|---|---|
| NHTSA overall rating | 5★ (2020) | 5★ (2021) |
NHTSA New Car Assessment Program, most recent rated model year (public domain).
Fuel, emissions and price
| Audi S3 | Mercedes-Benz C-Class | |
|---|---|---|
| Official combined fuel use, Canada | 9.2 l/100 km (2026) | — |
| Real-world use in Europe, petrol | 10.0 l/100 km | 10.9 l/100 km |
| Real-world use in Europe, diesel hybrid | — | 6.0 l/100 km |
| Real-world use in Europe, petrol hybrid | — | 8.5 l/100 km |
| Real-world use in Europe, diesel | — | 6.3 l/100 km |
| Official CO₂ of new cars in Europe | 183 g/km | 116 g/km |
| Average power of new cars in Europe | 228 kW (306 hp) | 152 kW (203 hp) |
| Average mass in running order | 1,579 kg | 1,818 kg |
| Dutch list price when new (median) | €63,627 | €54,166 |
| Average odometer in Finland | 169,000 km | 248,000 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).