Performance & drive
What it’s like to drive, and how quiet it is
The M850i proves highly responsive, muscular and extremely rapid in any scenario (0-62mph officially takes just 3.9sec). It's certainly the engine to choose if performance is key to you. Meanwhile, the 840d should impress (we're yet to try it in the Gran Coupe, but know it well from drives in the two-door 8 Series) with effortless shove from the get-go; but, in case you haven't noticed, diesel isn't that popular these days.
So, for the best blend of performance and economy, we'd suggest the 840i. It pulls consistently at low to mid revs, but, compared with the M850i, you have to work it harder to find its absolute turn of pace. Still, in a sporty car, revving the engine is all part of the fun, and while a Porsche Panamera 4S is quicker, the 840i will dispatch the 0-62mph dash in a highly respectable 5.2sec. In any iteration, the 8 Series' standard eight-speed automatic gearbox is quick, smooth and highly adept at picking the right gear for any given situation.
The 8 Series' steering is sweeter than the A7 Sportback’s, if not quite as direct as the Panamera’s. It’s light (although you can ramp up its weight should you wish by engaging the sportiest of the driving modes), but because its weight builds progressively from the start of every turn, it still endows you with heaps of confidence.
Rather like the Mercedes CLS, the adaptive suspension’s Comfort mode allows the Gran Coupé quite a lot of float to help it deal with gently heaving roads in a relaxed fashion. If you fancy a bit more control, simply pop it in the midway Sport or most extreme Sport Plus mode and it’ll hunker down.
Sharper ruts, which are getting more prevalent on our UK roads, do cause it to jolt more abruptly, but nothing like as badly as the CLS can. If you want the best ride quality, avoid the stiffer-sided Performance Tyres (optional on the 840i/ 840d and standard on the M850i), which exacerbate any surface imperfections.
Also, if you like a smooth ride and are less bothered about handling prowess, try an A7 Sportback. It’s one of the Gran Coupé’s most cosseting rivals, and not only for ride; it’s quieter at motorway speeds, with less wind and road noise, although the Gran Coupé keeps those at bay just as well as a Panamera or CLS.