Parkers overall rating: 4.5 out of 5 4.5

Miles per pound (mpp) Miles per pound (mpp)

Reliable fuel consumption data for comparison purposes is not available for this model.

Fuel economy

A more stringent standard for fuel economy (WLTP) was introduced from September 2017, and this model was not required to undergo that test. Its fuel economy measured under the previous test system was 28 - 28 mpg. However these figures are less likely to be achievable in real world driving and so should never be compared to another car's mpg which was measured under the newer, more realistic WLTP system.

There is no economical version of this car and Mercedes CLS 63 AMG running costs are expectantly high; if you’re looking for economy and efficiency then the CLS 350 CDI is the car for you. Still, this range-topping performance Coupe-saloon or Shooting Brake can in theory achieve 28.0mpg.

The reality is the car encourages you to drive it hard, and getting anywhere near that figure is unlikely. Expect to achieve somewhere between 20-24mpg in mixed everyday use, and slightly over 25.0mpg on longer runs.

It’s easy to forgive such an enthralling car this fuel misgiving though, and the 80-litre fuel tank capacity does at least mean you can travel around 400 miles between fills.

The CLS 63 AMG does sit in group 50 for its insurance, so expect to pay healthily for annual cover.

Mercedes CLS 63 AMG emissions are actually pretty good considering the performance on offer. Thanks to standard-fit stop start it emits 235g/km of CO2, which even keeps annual road tax to a reasonable level too.

It’s a firm with a reputation for well-built cars, so Mercedes CLS 63 AMG reliability isn’t likely to be an issue.

The hand-built engines are constructed to very tight tolerances and the technology used to extract all that power is thoroughly tested before being approved for fitting to production engines. That 5.5-litre twin-turbo V8 petrol engine is used on the SLK, SL, E-Class, G, ML and GL AMG models too, with no previous reports of any reliability issues.

There is a lot of technology on the CLS 63 AMG though, and while Mercedes electrics aren’t known for going haywire it would be remiss of us not to suppose there could be some potential problems down the line – even if it’s just a faulty sensor.

Ongoing running costs

Road tax (12 months) £520 - £615
See tax rates for all versions
Insurance group 48 - 50
How much is it to insure?