BMW 6-Series

This should be the perfect marriage – BMW’s incredibly powerful twin-turbo 3-litre diesel engine and the suave yet practical 6-series coupe. And it does have its appeal: the engine is super-torquey (how does 428lb ft @ 1700rpm sound?) and provides effortless performance, the six-speed automatic gearbox is silky smooth and the interior is beautifully finished. As a place to spend lots of time you can only conclude that the 635d Sport is a mighty impressive car.

There are niggles though, and the more miles you cover the more annoying they become. First there’s the diesel clatter, which is pretty horrendous at cold but never really dies away even at a cruise. The uninspiring drone really detracts from the experience and the engine feels slow to rev, overloaded with its own inertia. In a supposedly sporty coupe that should relish being used properly, it’s hard to ignore an engine that’s much happier pottering than charging to the red zone.

Then there’s the ride – agitated, noisy and totally unable to deal with short, sharp bumps. Body control is good when you do decide to work the chassis hard, but you only discover its excellent neutral balance after ignoring all the signals that are screaming at you to slow down – at seven-tenths the 635d feels ragged and ill-sorted. The £2200 Sport package adds 19in wheels – as well as Sports seats, a three-spoke M steering wheel and a few other ‘sporty’ touches like anthracite headlining – and in combination with 35-profile run-flat tyres they really hobble the big coupe.

It’s a confused and confusing car, the 635d Sport, reluctant to be driven like a sports car and without the sophistication of ride to be a true GT. At £56,110 it’s about £1000 less than the 650i, which has 362bhp and runs from 0-62mph in 5.2 seconds as opposed to 6.3. The 650i is also more refined, more agile and sounds fantastic. Ignore that too, though. M6 prices have crashed to around £47,000 on the used market. Now that’s one 6-series I would recommend to anyone…

Specifications