2021 What Car? Reliability Survey: coupés, convertibles and sports cars

We reveal the most – and least – dependable cars up to five years old, based on the experiences of more than 16,000 owners...

2019 Audi TT Coupe front red

Most reliable coupés, convertibles and sports cars

=1. Audi TT Coupé/Convertible (2015-present)

Reliability rating 100%

What went wrong? Nothing

The TT has long been one of our favourite coupés, and it’s exemplary when it comes to dependability. Of the TT owners who participated, none told us their car had gone wrong in the previous 12 months, providing the model with a perfect reliability rating of 100%.

Owner’s view "In my opinion, the TT’s finish and quality are unmatched by its rivals"


=1. Mini Convertible (2016-present)

Mini Convertible front three quarters

Reliability rating 100%

What went wrong? Nothing

It may not be the most practical drop-top you can buy, but the Mini excels when it comes to dependability. With no faults reported by any of the owners who contacted us, it ties with the Audi TT with full marks.

Owner’s view "The build quality is excellent inside and out and reliability has been spot on"


3. BMW 2 Series Coupé/Convertible (2014-present)

BMW 2 Series Convertible

 Reliability rating 96.9%

If you need more space than the TT or Mini can offer, the 2 Series is a very dependable choice. Owners told us that 9% developed a fault, all bodywork related. Half were fixed for free and the rest cost their owners between £301 and £500. Although 50% took more than a week to put right, the others were back on the road in a day or less.


Least reliable coupés, convertibles and sports cars

1. Porsche 718 Cayman/Boxster (2016-present)

Porsche Cayman T front

Reliability rating 73.5%

What went wrong? Bodywork 27%, suspension 20%, engine 13%, engine electrics 7%, sat-nav 7%

Not only does the Cayman cost a lot to fix, but it can also take a long time to put right. Fifty-three percent of 718s went wrong, and only 67% of repairs were free; some bills came to a few hundred pounds, while 8% cost more than £1500. Repairs took up to a week for 83% of cars, but 8% took more than a week.

Owner’s view "The Cayman is a stonking drive when it’s running. Unfortunately, mine is by far the most unreliable car I have ever owned"


2. Fiat/Abarth 124 Spider (2016-2019)

Fiat 124 Spider front

Reliability rating 84.5%

Owners told us that 33% of their 124 Spiders went wrong, with electrical issues the main concern, followed by bodywork and engine woes. Repair bills were minimal, though; 91% of cars were fixed for free and no bills exceeded £200. Although 46% of cars were fixed within seven days, 36% took more than a week.


3. Mazda MX-5 (2015-present)

Mazda MX-5 2.0 Sport Nav+

Reliability rating 95.1%

The MX-5 scores well for reliability, but stiff competition has relegated it to the bottom three. Eighteen percent of cars went wrong, with battery and bodywork the most common problem areas. Half were fixed for free and no bills exceeded £200. Although half were put right in a day or less, 25% took more than a week.


Reliability of coupés, convertibles and sports cars aged up to five years old

Rank Make and model Score
=1. Audi TT 2015-on 100%
=1. Mini Convertible 2016-present 100%
3. BMW 2 Series Coupé/Convertible 2014-present 96.9%
4. BMW 4 Series Coupé/Convertible 2014-2020 96.3%
5. Audi A5 2016-present 95.8%
6. Mazda MX-5 2015-present 95.1%
7. Fiat / Abarth 124 Spider 2016-2019 84.5%
8. Porsche 718 Cayman/Boxster 2016-present 73.5%