BMW 4 Series vs Porsche 911
The Porsche 911 has the better MOT record of the two — 9.7% fail rate versus 11.8% for the BMW 4 Series across comparable years. The biggest single difference is tyres, where the 4 Series records failures noticeably more often.
11.8%
4 Series fail rate
9.7%
911 fail rate
2.11pp
Difference
Side by side
| Metric | BMW 4 Series | Porsche 911 |
|---|---|---|
| MOT tests analysed | 567,497 | 252,686 |
| Pass rate | 88.2% | 90.3% |
| Fail rate | 11.8% | 9.7% |
Where they differ
| Category | 4 Series | 911 |
|---|---|---|
| Tyres | 7.3% | 2.3% |
| Lighting & signalling | 2.4% | 4.8% |
| Emissions & environmental | 0.0% | 1.9% |
| Visibility | 1.6% | 0.0% |
| Suspension | 1.4% | 1.6% |
| Brakes | 1.9% | 2.0% |
Methodology & source. Dataset: DVSA MOT testing data (2021,2022,2023,2024,2025). Data last updated 2026-07-27. Figures reflect MOT-testable defects only — read the methodology for how these are calculated and what they don't measure.