Audi
S6
BMW
M5
Audi S6 vs BMW M5: 2024 Comparison
The short answer
Based on available data, the BMW M5 comes out ahead of the Audi S6 on fuel economy and power. Check the specs table and owner sentiment below for the full comparison before deciding between the two. Both are covered by real owner reports on CarWizz.
Specs side by side
What owners say
S6
Overall
Sentiment is mixed and heavily dependent on the specific generation and powertrain. For the C7 generation (approximately 2013-2018) with the twin-turbo 4.0L V8 (4.0T), the vehicle is widely praised for its potent performance, refined luxury, and high-speed cruising capability, described as stable and quiet even at high speeds (e.g., 155 mph / 250 km/h). However, this generation is overshadowed by a very frequent and severe concern regarding catastrophic turbocharger failure, linked to oil screen design flaws, which can lead to engine destruction and extremely high repair costs.
Best version to buy
Insufficient owner data available to declare a consensus "best" version. For the C7 generation (4.0T), there is a strong emphasis on purchasing a vehicle with a comprehensive extended warranty that explicitly covers the turbochargers.
Known issues
- ⚠Catastrophic turbocharger failure (C7 4.0T V8): Caused by restrictive oil screens leading to oil starvation, turbo failure, and potential engine destruction. Repair costs are extremely high ($9,000-$12,000 USD at a dealer).
- ⚠Software and electronic issues (S6 e-tron): Numerous software glitches requiring multiple service visits, though not necessarily impacting drivability. Frequency: recurrent.
- ⚠Carbon buildup (C6 V10 models): Leads to rough running and performance issues, particularly noted on 2007-2008 models. Frequency: recurrent.
M5
Overall
Sentiment is sharply divided by generation and is heavily influenced by ownership costs. The E60 generation (V10 S85 engine) is universally described as an unreliable "money pit" and "heap of junk" with catastrophic engine failure risks, particularly concerning rod bearings, leading to extremely high maintenance costs. The F90 generation (V8 S63 engine) receives a more positive reception for its brutal performance, all-wheel drive capability, and modern luxury, but is still acknowledged as a very expensive vehicle to maintain properly.
Best version to buy
F90 Competition (pre-hybrid V8): This generation is frequently cited as the "last good M5," praised for its reliability relative to the V10, monstrous performance from its twin-turbo V8, and attractive design. It is seen as a peak of the traditional M5 formula before the added weight and complexity of the hybrid G90.
Known issues
- ⚠Catastrophic engine failure (E60 V10 S85): Rod bearing failures leading to seized engines; described as one of the least reliable BMW engines ever made. Frequency: very frequent.
- ⚠Extremely high maintenance/repair costs: Described as an "absolute fortune" to maintain, with reports of $20,000+ spent over 10 years for low-mileage cars; major service bills anticipated as mileage approaches 100,000 km.
- ⚠Hybrid system and weight drawbacks (G90): Numb brake feel due to regen, excessive mass, and electromechanical systems that detract from driver engagement; noted quality control issues like missing door assemblies and non-functional heaters…
The verdict
The BMW M5 is the better choice for most buyers.
It has better fuel economy on its best-equipped version than the Audi S6, based on the data above. If power matters more to you than running costs, the Audi S6 is worth a closer look instead.
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Frequently asked questions
Which is more reliable, the Audi S6 or the BMW M5?
Owner reports show similar reliability sentiment for the Audi S6 and the BMW M5. Check the known issues listed above for specific differences between the two.
Which is better for families, the Audi S6 or the BMW M5?
Both seat a similar number of passengers based on our data. The Audi S6 is classed as a Sedan, the BMW M5 as a Station wagon, which affects cargo space and ride height for family use.
Which has better fuel economy, the Audi S6 or the BMW M5?
The BMW M5 is more fuel-efficient on paper: 2.0 L/100km combined versus 9.2-9.4 L/100km for the Audi S6, based on the best-equipped catalogued version of each.
Which is cheaper to maintain, the Audi S6 or the BMW M5?
Exact maintenance costs aren't in our data, but owner reports mention cost-related concerns more often for the Audi S6 than the BMW M5. See the known issues comparison above.