BMW 8 Series vs Mercedes S-Class coupe: you choose

BMW says the new 8 Series coupe, in 4.4-litre V8-powered, 523bhp M850i form, is supposed to straddle a gap in the market. Namely, the canyon between the Porsche 911, and associated sports cars, and the Mercedes S-Class Coupe – one of Top Gear’s very favourite luxury waft-mobiles.

Still, purely in silhouette and layout, the M850i looks much more of a dead-ringer for the latest Mercedes S560 than it does, say, a 911 Carrera GTS. So, allow us to present the must-know numbers for these two-tonne German cathedrals of power, opulence and technical one-upmanship. And then, you must decide. Are you team 8 Series, or team S-Class?

Power

The M850i’s twin-turbo, 4.4-litre V8 has been substantially revised with stronger internals and slicker internal friction for its role in BMW’s flagship. The results are 523bhp and 553lb ft – which, for £101k, has the Mercedes licked.

For similar money – £103,745 to be precise - you’re into the S560, complete with a 4.0-litre bi-turbo V8. In the AMG GT R, it’s good for 577bhp, and can produce over 600bhp in the E63S. But for its more relaxed S Coupe role, Mercedes becalmed its temper to the tune of 465bhp and 516lb ft. First blood to BMW then. To top the M850i’s outputs, you’ll be needing the AMG S63 coupe, which develops 602bhp and 664lb ft. You’ll also be needing a whopping £127,555.

Speed

The M850i isn’t just more powerful than the S560 – it’s got twice as many wheels applying that power to the road. That means the four-wheel drive BMW dispatches 0-62mph in 3.7 seconds and predictably tops out at an S560-matching 155mph. Meanwhile, the big bad Benz has loped from 0-62mph, pushed along by its rear wheels alone, in 4.6 seconds. Quick enough, for a canal boat. But almost a second behind that rampant BMW.

Economy

This isn’t so much a study in saving buyers of £100k V8 coupes at the pumps, and more working out how many times you’ll need to stop on the run to your luxury Scottish castle, or Mediterranean villa. BMW claims 28.3mpg for the M850i, while the Mercedes is optimistically rated at 34mpg. We’d reckon on low-to-mid twenties for either, and with 80 or so litres on board, you’ll be good for a 500-mile schlep. Aaand relax.

Interior

Bit more subjective, this one. You’d be happy to while away miles in both, but there’s something more baroque and classical about the Mercedes cabin, with its broad swoop of bulbous leather dash, and cute metal vents. Those slim buttons and the flash screen emphasise width and a grandiose sense of space. It’s not overtly sporting.

Enter the BMW. Its digital dials appear to have been borrowed from a Eurofighter. The centre console is festooned with mode settings, a fussy gear selector and a nest of glossy toggles. It’s a modern place to be, but very traditional BMW: businesslike, driver orientated, and pretty much free of flourishes. Still, can’t you just smell that leather from here?

Herends our whistlestop tour of Mercedes and BMW’s range-topping land-yachts. Now, we invite you to choose your favourite – or suggest a suitable alternative…