The short answer
Based on available data, the Audi RS4 comes out ahead of the Audi S4 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.
Overall
Sentiment is deeply polarized, split between passionate admiration for the driving experience and significant criticism regarding ownership costs and reliability. The naturally aspirated 4.2L V8 engine is universally praised for its sound, high-revving character (8000 rpm redline), and raw, engaging feel, which owners describe as a defining and special characteristic. The vehicle is celebrated for its handling, often attributed to the DRC (Dynamic Ride Control) hydraulic suspension, which provides a planted, confident feel.
Best version to buy
Insufficient owner data available to designate a specific model year or trim as "best." The B7 generation (2006-2008) is the primary subject of discussion. The manual transmission is strongly implied as the preferred choice over the automated single-clutch transmission due to reliability concerns with the latter.
Known issues
Overall
Sentiment is deeply divided by generation and is heavily dependent on owner expectations and financial preparedness. For the B8/B8.5 generation (circa 2010-2016) with the supercharged 3.0T V6, feedback is overwhelmingly positive, praising the engine as a "beast" with great power, low-end torque, and a strong reliability track record when properly maintained. This generation is frequently described as a practical, fast, and comfortable daily driver that blends performance with family usability.
Best version to buy
B8.5 Generation (circa 2013-2016): This iteration of the supercharged 3.0T V6 is consistently highlighted for its proven reliability, strong performance, and the inclusion of a desirable dual-clutch (S tronic) or manual transmission in some models. It is seen as having resolved early B8 issues while avoiding the potential new-engine concerns of the later B9 and the catastrophic timing issues of the older B6/B7 V8 models.
Known issues
The verdict
The Audi RS4 is the better choice for most buyers.
It has better fuel economy on its best-equipped version than the Audi S4, based on the data above. If power matters more to you than running costs, the Audi S4 is worth a closer look instead.
Other comparisons
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Which is more reliable, the Audi RS4 or the Audi S4?
Owner reports show similar reliability sentiment for the Audi RS4 and the Audi S4. Check the known issues listed above for specific differences between the two.
Which is better for families, the Audi RS4 or the Audi S4?
Both seat a similar number of passengers based on our data. The Audi RS4 is classed as a Station wagon, the Audi S4 as a Sedan, which affects cargo space and ride height for family use.
Which has better fuel economy, the Audi RS4 or the Audi S4?
The Audi RS4 is more fuel-efficient on paper: 9.9 L/100km combined versus 10.2 L/100km for the Audi S4, based on the best-equipped catalogued version of each.
Which is cheaper to maintain, the Audi RS4 or the Audi S4?
Exact maintenance costs aren't in our data, but owner reports mention cost-related concerns more often for the Audi S4 than the Audi RS4. See the known issues comparison above.