Which will lose less value: BMW M135i or Porsche Cayman S?

A reader is looking to buy a performance car but wants to keep depreciation to a minimum...

BMW M135i vs Porsche Cayman

I’m intending to buy a second-hand sports car, either a Porsche Cayman S or a BMW M135i [hot hatch], and would appreciate some advice about which car will lose the least in depreciation. 

I was intending to buy a 2015 Porsche Cayman S, but due to Brexit uncertainties and the possibility I might need to sell it in six to nine months time, I'm wondering if I’d be better off buying an M135i instead. My understanding is that the Porsche could lose a few thousand pounds over nine months but the BMW could lose far less than this. 

Used Porsche Cayman 2013-2016 side driving

Can you tell me how much each of these cars, first registered in 2015 and with 20,000 miles on the clock, would depreciate over a six-to-nine-month period? 

Chris Heffernan

What Car? says

For a detailed analysis of the depreciation of each of these models, we contacted valuations expert Cap HPI. It told us that the Cayman's current value is around £36,500 and in May 2020 it would be worth £34,250, a difference of £2250. In contrast, the BMW is currently worth £15,295 and would be valued just £445 lower at £14,850 in May 2020.

Robert Hester, the company’s short-term forecast manager, added: “Either car would be a good choice, as both have strong desirability factor and registration volumes are very low, which means there will never be that many available in the used market at any one time.

“The Porsche is probably the more desirable of the two, but with that comes a bigger initial outlay followed by higher running costs. The Porsche is also very spec-sensitive, and a poorly specced car may be difficult to move on at a later date.

“The BMW is also desirable and comes with a much lower initial outlay. Again, the right colour and spec are the key to being able to sell again quickly. Running costs for the BMW are likely to be slightly lower than for the Porsche, too.

“In both cases, to be able to achieve a quick sale and maximum return, a full recognised history is paramount.

"Looking at depreciation, our forecast has the Porsche losing more over the next 12 months than the BMW, although the initial cost of the Porsche is greater, so in relative terms the rate of depreciation of both cars is similar.”

It's worth bearing in mind some other factors as well. If you’re buying on a personal contract purchase (PCP) deal, check the terms and conditions to ensure you won’t incur a penalty for ending the agreement early. Also, if you buy from a dealer, you’ll be paying the top retail price. And if you then sell the back to a dealer, you’ll be doing so at the lowest trade-in price, so you’re likely to lose less money if you sell the car privately. 

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Best used sports cars for less than £35,000

Want a sports car but don’t have unlimited funds? Then have we got a treat for you.

The best modern sports cars combine adrenaline-pumping performance with exhilarating handling, but also throw in a generous helping of modern technology and high safety standards. And while new models don’t come cheap, a combination of high depreciation and low average mileages often makes a used sports car a particularly savvy buy.

Here we’ve brought together the ten best used sports cars you can buy, and rated them taking into account value, price and their ability to deliver a thrilling driving experience.

Best used sports cars

10. Lotus Evora

Used Lotus Evora

It might feel a bit cheap and flimsy inside, but there’s no faulting the driving experience offered by the Lotus Evora. Both the standard, naturally-aspirated car and the supercharged ‘S’ deliver scintillating performance, and with Lotus’s typically excellent chassis engineering behind it, the Evora’s also superb to drive. You might have to put up with a little more engine and road noise than some rivals, mind you.

We found: 2011 Lotus Evora, 33,700 miles, £31,990

Read the full Lotus Evora review

9. Nissan GT-R

Used Nissan GT-R

Striking looks and Earth-shattering performance both in a straight line and around a bend – what’s not to like about the Nissan GT-R? Well, there's its interior for starters, which feels a bit out of date these days and isn't the most interesting to look at. However, you’ll soon forget that quibble once you’re out on the move, because the sledgehammer shove of its turbocharged V6, combined with the vast levels of grip the GT-R has around corners, is truly breathtaking.

We found: 2010 Nissan GT-R 3.8 V6, 42,277 miles, £33,990

Read the used Nissan GT-R review

8. Lotus Elise

Used Lotus Elise

The Evora’s little brother, the Lotus Elise has always nailed its target audience. Its ethos is as a pared-down roadster with lightness and involvement front and centre, so don’t expect much in the way of equipment. But if you want a two-seat sports car that offers the ultimate lightweight driving experience with a modicum of usability, there’s little better.

We found: 2016 Lotus Elise S, 16,958 miles, £32,950

Read the used Lotus Elise review