Audi
TT
Mercedes-Benz
SLK
Audi TT vs Mercedes-Benz SLK: 2020 Comparison
The short answer
Based on available data, the Mercedes-Benz SLK comes out ahead of the Audi TT 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
TT
Overall
Sentiment is generally positive, with strong affection for the TT's distinctive design, driver-focused interior, and engaging driving dynamics, particularly in higher-performance TTS and TT RS variants. The vehicle is consistently praised for its practicality as a two-seater, with surprisingly usable boot space, especially with rear seats folded. However, owner sentiment is heavily bifurcated by generation and maintenance history.
Best version to buy
For the Mk3 generation (2015-2023), the TTS is frequently recommended as the best balance of performance, daily comfort, and value over the base TT, while the TT RS is celebrated as the ultimate performance variant with its unique 5-cylinder engine. For earlier generations, the 225-hp Quattro model of the Mk1 is often favored over the front-wheel-drive 180-hp version.
Known issues
- ⚠**Mk1/Mk2 Generations:** Timing belt/chain system failures: Critical maintenance item on 1.8T engines; belt must be replaced every 60k-80k miles (97k-129k km) with water pump; chain stretch issues on later EA888 and VR6 engines.
- ⚠Electrical gremlins: Intermittent faults, failing instrument clusters (pixel loss, inaccurate gauges), faulty comfort control modules preventing window operation. Frequency: recurrent.
- ⚠DSG (S Tronic) mechatronic unit failures: High-cost repair for automatic models; requires documented service or rebuild at high mileage. Frequency: recurrent.
SLK
Overall
Sentiment is mixed and heavily dependent on generation, specific engine, and ownership expectations. For the earliest R170 generation (1997-2004), owners report these as surprisingly reliable and robust budget-friendly classic convertibles when purchased cheaply (e.g., £1,000 GBP / ~$1,260 USD), praised for their bulletproof engines, comfortable heated seats, and effective "Airscarf" neck heating system. The hardtop convertible mechanism is generally seen as a durable asset, though its seals require regular lubrication.
Best version to buy
Insufficient owner data available to declare a definitive "best" version. Isolated positive remarks exist for the R170 for its simplicity and value, and for the R172 SLK55 AMG for its powerful V8 engine.
Known issues
- ⚠Hydraulic convertible top failure (R171): roof operation slows, makes loud noises, leaks hydraulic fluid (causing skin irritation), eventually fails completely; repair cost often cited as exceeding vehicle value. Frequency: recurrent.
- ⚠Engine timing chain/balance shaft issues (R171 M272 V6): timing chain noise, potential for catastrophic failure due to faulty balance shaft gears on 2004-2007 models. Frequency: recurrent.
- ⚠Electrical faults and sensor failures: various error codes for oxygen sensors, air pumps, camshaft timing sensors, power steering pressure valves, and other components; can cause rough running or warning lights. Frequency: recurrent.
The verdict
The Mercedes-Benz SLK is the better choice for most buyers.
It has stronger reliability sentiment in owner reports than the Audi TT, based on the data above. If the specific known issues on the Mercedes-Benz SLK are a dealbreaker, the Audi TT is worth a closer look instead.
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Frequently asked questions
Which is more reliable, the Audi TT or the Mercedes-Benz SLK?
Owner reports lean more positive on reliability for the Mercedes-Benz SLK than the Audi TT. See the known issues comparison above for the specific concerns owners report on each.
Which is better for families, the Audi TT or the Mercedes-Benz SLK?
Both seat a similar number of passengers based on our data. The Audi TT is classed as a Cabriolet, the Mercedes-Benz SLK as a Roadster, which affects cargo space and ride height for family use.
Which has better fuel economy, the Audi TT or the Mercedes-Benz SLK?
The Mercedes-Benz SLK is more fuel-efficient on paper: 8.4 L/100km combined versus 8.7 L/100km for the Audi TT, based on the best-equipped catalogued version of each.
Which is cheaper to maintain, the Audi TT or the Mercedes-Benz SLK?
Exact maintenance costs aren't in our data, but reliability signals above are the closest proxy: fewer reported issues generally means lower repair costs over time.