BMW
i8
Porsche
911
BMW i8 vs Porsche 911: 2025 Comparison
The short answer
The BMW i8 offers fuel economy, while the Porsche 911 excels at power instead. Choose the BMW i8 if you prioritize fuel economy in daily driving, or the Porsche 911 if power matters more for your needs. Both are covered by real owner reports on CarWizz.
Specs side by side
What owners say
i8
Overall
Mixed sentiment with a clear divide between perception and ownership experience. The vehicle is widely criticized for a perceived mismatch between its dramatic, supercar-inspired styling and its actual performance capabilities, particularly when compared to contemporary BMW M cars like the F80 M3. This has led to a reputation in some circles as a "poser car" or a "lawnmower in a supercar body." However, a strong counter-narrative from long-term owners praises the i8 as a reliable, surprisingly fun-to-drive grand tourer with low maintenance costs and exceptional fuel efficiency for its appearance.
Best version to buy
Insufficient owner data available to declare a consensus "best" version. Owner discussions mention both the Coupe and Roadster (2018+) variants, with the Coupe noted for retaining small rear seats and slightly lower weight, while the Roadster sacrifices that practicality for an open-air experience.
Known issues
- ⚠Perceived performance deficit: very frequent criticism that the hybrid powertrain's output does not match the supercar styling, with specific comparisons noting it was slower in some metrics than the F80 M3 launched the same year.
- ⚠High-voltage (HV) battery reliability: isolated reports of HV battery failures requiring repair, noted as being a manageable DIY fix involving replacing individual faulty cells rather than the entire pack. Frequency: isolated.
- ⚠Fake engine sound: use of an artificial sound generator (speaker) noted as a negative by some enthusiasts. Frequency: isolated.
911
Overall
Sentiment is deeply polarized and varies significantly by generation and model. Long-term ownership satisfaction is frequently described as very high, with many owners reporting the car living up to or exceeding lifelong expectations. The 911 is often cited as a benchmark for driver engagement and is recognized as a highly satisfying vehicle to own.
Best version to buy
997.2 Generation: Specifically praised as the "absolute best modern 911" for combining hydraulic steering, a manual transmission, and a modern enough interior. The 997.1 Turbo is also highlighted as a desirable, proven performance variant with a durable engine and dry-sump oiling.
Known issues
- ⚠Extremely high maintenance and repair costs: Major engine or transmission failure can cost more than the car's value, and parts are exceptionally expensive. Frequency: very frequent.
- ⚠Turbo lag in modern turbocharged engines (991.2, 992): Noted as a significant dynamic flaw, with criticism that reviewers downplay its presence. Frequency: recurrent.
- ⚠Interior material quality and durability: Hard plastics, manual seats in base models, and specific issues like peeling door cards on 991 models left in the sun. Frequency: recurrent.
The verdict
The BMW i8 is the better choice for most buyers.
It has stronger reliability sentiment in owner reports than the Porsche 911, based on the data above. If the specific known issues on the BMW i8 are a dealbreaker, the Porsche 911 is worth a closer look instead.
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Frequently asked questions
Which is more reliable, the BMW i8 or the Porsche 911?
Owner reports lean more positive on reliability for the BMW i8 than the Porsche 911. See the known issues comparison above for the specific concerns owners report on each.
Which is better for families, the BMW i8 or the Porsche 911?
Both seat a similar number of passengers based on our data. The BMW i8 is classed as a Roadster, the Porsche 911 as a Coupe, which affects cargo space and ride height for family use.
Which has better fuel economy, the BMW i8 or the Porsche 911?
The BMW i8 is more fuel-efficient on paper: 2 L/100km combined versus 11.6-11.8 L/100km for the Porsche 911, based on the best-equipped catalogued version of each.
Which is cheaper to maintain, the BMW i8 or the Porsche 911?
Exact maintenance costs aren't in our data, but owner reports mention cost-related concerns more often for the Porsche 911 than the BMW i8. See the known issues comparison above.