We tested a 518d in 'Luxury' specification, a mid-grade trim, with the optional paddle-shifted eight-speed torque convertor automatic and variable damper control – all of which would set you back £35,735.
This, it appears, is a particularly fine combination to opt for. Firstly, you get the slick-shifting, easy-going ZF eight-speed automatic, the wide ranging ratios of which make good use of the diesel's output.
Secondly, besides vast amounts of kit, this trim level equips the 5-series with 18-inch alloy wheels and tyres with a substantial amount of sidewall. Consequently the 5-series rides in a pliant, cosseting fashion that befits its executive saloon nature.
Lastly, and wrapping up the package neatly, the addition of the variable damper control gives the 5-series a wider-ranging breadth of talent than the standard 5-series. A new Comfort+ mode delivers a smoother ride than was possible previously, or, if desired, a Sport mode offers improved responses, minimised body roll and better comfort in high-speed cornering situations.
Is the 518d's engine capable of summing up the kind of performance and refinement that a luxury saloon necessitates though? Well, almost. The 0-62mph sprint is dispatched in a sensible 9.4sec, and in-gear acceleration proves swift enough to not be an annoyance. Above 1500rpm the diesel pulls with comparative vigour, up until around 3500rpm, after which its performance tails off.
Fortunately, despite the narrow 2000rpm spread of power, the sheer number of gear ratios on offer means progress is always swift and the diesel is always kept turning within its favoured range of crank speed. This is beneficial for both the engine and the driver, as worked hard the diesel engine is predictably noisy after 3000rpm – or at full throttle – but the rapid gear changes usually keep it below that speed.
Driven in a sensible fashion, however, or once up to cruising speeds, the engine is quiet and – unlike the BMW X3 – there's no persistent light diesel clatter in the background. The only oddity is that the ZF gearbox is very keen to get into higher gears, for efficiency reasons, which can lead to the engine being laboured somewhat. Once the revs drop below 1500rpm an audible low-frequency drone fills the cabin and a light vibration can be felt; drop down a gear – from seventh to sixth at 30mph, for example – and smoothness and silence is instantly restored.
The engine is otherwise refined, barring its full-throttle, rev-counter roaming vocality – although the swift-acting stop-start system does serve to intermittently remind you that it's definitely a diesel, with the momentary silence and then eruption of noise highlighting how much quieter a petrol would be.