BMW
M6
Owner report available
BMW
M8
Owner report available
BMW M6 vs BMW M8
The short answer
The BMW M6 offers fuel economy, while the BMW M8 excels at power instead. Choose the BMW M6 if you prioritize fuel economy in daily driving, or the BMW M8 if power matters more for your needs. Both are covered by real owner reports on CarWizz.
Specs side by side
What owners say
M6
Overall
Sentiment is deeply polarized and highly conditional. The vehicle is universally revered for its high-revving 5.0L V10 (S85) engine, described as an "insanely fast" and "brilliant" powerplant above 5,000 RPM, offering a unique and thrilling driving experience that creates significant owner pride and excitement. However, this is heavily counterbalanced by very frequent and severe criticism regarding legendary reliability concerns and extreme ownership costs.
Best version to buy
Insufficient owner data available to designate a specific model year or trim (e.g., Competition Package) as the "best." The primary differentiator discussed is transmission choice. The 6-speed manual (6MT) is highly prized for its rarity, driver engagement, and because it avoids the notorious reliability issues of the SMG III automated manual transmission.
Known issues
- Rod bearing failures in the S85 V10 engine: considered a critical, well-documented flaw requiring preventative replacement; catastrophic engine failure risk. Frequency: very frequent.
- SMG III transmission reliability: prone to major failures, expensive repairs, and criticized for poor drivability in daily use. Frequency: very frequent.
- Throttle actuator failures: another common and expensive fault with the S85 engine. Frequency: very frequent.
M8
Overall
Mixed sentiment with a clear divide between appreciation for its capabilities and criticism of its character. The vehicle is widely acknowledged as extremely fast, comfortable, luxurious, and built to a high quality with tight assembly tolerances. It is consistently described as an excellent grand tourer that does everything well, offering a blend of performance, technology, and daily usability.
Best version to buy
Insufficient owner data available to declare a consensus "best" version (e.g., Coupe vs. Gran Coupe, Competition vs. base).
Known issues
- Lack of driving emotion/excitement: described as bland, boring, or lacking visceral feel despite high performance. Frequency: very frequent.
- Ignition coil and coolant hose failures: on the hot-V 4.4L V8 in related models (M6), noted as a potential age-related concern for the M8. Frequency: isolated.
- Ride quality: described as very stiff, to the point of compromising its grand touring comfort, especially when compared to the M850i. Frequency: recurrent.
The verdict
The BMW M6 is the better choice for most buyers.
It has better fuel economy on its best-equipped version than the BMW M8, based on the data above. If power matters more to you than running costs, the BMW M8 is worth a closer look instead.
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Frequently asked questions
Which is more reliable, the BMW M6 or the BMW M8?
Owner reports show similar reliability sentiment for the BMW M6 and the BMW M8. Check the known issues listed above for specific differences between the two.
Which is better for families, the BMW M6 or the BMW M8?
Both seat a similar number of passengers based on our data. The BMW M6 is classed as a Sedan, the BMW M8 as a Coupe, which affects cargo space and ride height for family use.
Which has better fuel economy, the BMW M6 or the BMW M8?
The EPA rates the 2019 BMW M6 at 16–17 mpg combined and the 2025 BMW M8 at 17 mpg, depending on the version.
Which is cheaper to maintain, the BMW M6 or the BMW M8?
Exact maintenance costs aren't in our data, but owner reports mention cost-related concerns more often for the BMW M6 than the BMW M8. See the known issues comparison above.