Mercedes-Benz SLK vs Porsche Boxster
On MOT-testable defects, the Porsche Boxster (fail rate 13.8%) performed better than the Mercedes-Benz SLK (19.4%) across comparable years. The biggest divergence was suspension, where the SLK recorded failures more often.
19.4%
SLK fail rate
13.8%
Boxster fail rate
5.63pp
Difference
Side by side
| Metric | Mercedes-Benz SLK | Porsche Boxster |
|---|---|---|
| MOT tests analysed | 354,328 | 182,460 |
| Pass rate | 80.5% | 86.2% |
| Fail rate | 19.4% | 13.8% |
Where they differ
| Category | SLK | Boxster |
|---|---|---|
| Suspension | 9.1% | 3.8% |
| Emissions & environmental | 0.0% | 3.9% |
| Visibility | 2.6% | 0.0% |
| Tyres | 5.1% | 2.7% |
| Brakes | 5.1% | 3.6% |
| Lighting & signalling | 7.0% | 6.1% |
Methodology & source. Dataset: DVSA MOT testing data (2021,2022,2023,2024,2025). Data last updated 2026-07-01. Figures reflect MOT-testable defects only — read the methodology for how these are calculated and what they don't measure.