2015 Mercedes-Benz C-Class Pricing and Specs

You don’t have to fit run-flat tyres to your car, but it can be a lot more convenient. A decade or so ago, it was quite common to replace run-flat tyres with more conventional tyres as the ride quality of run-flats was relatively poor. These days, that isn’t the case to the same extent, and run-flats have come a long way.

But if you can’t get them in the correct size, then you have a problem that can be solved by fitting conventional tyres of the correct size, speed rating and load rating. A tyre shop should be able to sort this out for you.

The catch, of course, is that a conventional tyre won’t get you home if it deflates for any reason (as a run-flat is designed to do). The knock-on problem there is that a car designed for run-flats will not only not have a spare tyre, it won’t even have a physical space to put one. The solution then is to find a repair kit of the type found in many cars today. This amounts to a tin of repair solution which is added to the tyre through the valve and the tyre reinflated with the attached compressor.

I assume the noise you are unhappy with is road noise. You could try a Michelin tyre, which is probably your best option, but the tyres are run-flats, so you won't get a soft ride whatever the brand you fit.

Obviously you're in the market for a performance drive, and the biggest difference between your preferences is seats. Specifically, just two in the Porsche. So, despite the fact the Cayman has a pretty handy boot in the nose, it's never going to be as practical as a C-Class sedan. The 6.2-litre V8 in the (W204) C63 is a naturally aspirated dream. The sound and fury of 372kW/620Nm (in the Edition 507) driving the rear wheels is a rare pleasure, and on the right road, its balance and mid-range punch are sublime. The current (W205-based) C63 S's 4.0-litre turbo V8 just pips it on outputs (375kW/700Nm), but the biggest difference with that unit's forced induction is that all that torque is available from just 1750rpm. The new chassis is brilliant, and is even quicker point-to-point than the Edition 507. Then there's the Cayman. Although we've somehow missed seat time in the GT4, experience with previous ‘special' models, including the (881) Cayman R and GTS point to this being the purest (or purist's?) choice. The 3.4-litre atmo R produces 243kW/370Nm, the GTS 250kW/380Nm, and the 3.8-litre GT4 is at 283kW/420Nm. The Cayman's mid-engine layout, and ideal weight distribution makes it one of the most precise and agile sports cars on the planet. So if you can live with just the two seats (that aren't exactly easy to get in and out of), it's our pick in terms of outright driving enjoyment.