True MPG: most and least efficient cars revealed

What Car?'s laboratory tests use a real-world driving route to show what fuel economy you can really expect. So, what are the best and worst performing cars?...

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Steve Huntingford
19 January 2019

Mercedes-AMG GLC 43 front

=4. Mercedes-AMG GLC 43

True MPG 25.3mpg

If you get your thrills from blasting away from traffic lights and listening to a piercing V6 soundtrack, the GLC 43 is well worth a look. It’s even practical and easy to drive when you’re in family mode. But it's never what you'd call frugal.

Read our full Mercedes GLC review, or see what discounts are available


=4. Porsche Macan Turbo Performance Pack

Used Porsche Macan 14-present

True MPG 25.3mpg

The Macan Turbo is a rival for the GLC 43, and averaged the same 25.3mpg in our True MPG test. However, of the two, it's the Porsche that offers more precise handling.

Read our full Porsche Macan review


3. Mercedes S500 Cabriolet

Mercedes-Benz S-Class Cabriolet

True MPG 25.2mpg

While this version of the S-Class Cabriolet has now been superseded, the car itself remains on sale and is the best luxury drop-top you can buy.

Read our full Mercedes S-Class Cabriolet review, or see what discounts are available


2. Audi SQ5

New Audi SQ5 vs Mercedes-AMG GLC 43

True MPG 24.6mpg

Like the rival GLC 43 and Macan Turbo, the SQ5 is as heavy on fuel as it is light on its feet. It benefits from a beautifully built interior which features one of the best infotainment systems out there.

Read our full Audi SQ5 review, or see what discounts are available


1. Alfa Romeo Giulia Quadrifoglio

New Alfa Romeo Giulia Quadrifoglio vs BMW M3

True MPG 23.5mpg

Like so many cars in this bottom 10, the Giulia Quadrifoglio is designed for performance rather than efficiency. Indeed, it's our reigning Performance Car of the Year, which tells you just how good it is at the things it specialises in.

Read our full Alfa Romeo Giulia Quadrifoglio review, or see what discounts are available

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