The M760Li xDrive is a V12 powerhouse that will perhaps inevitably be an ultra-rare sight in the UK. But its 100 or so annual buyers are in for something of a treat.

Because BMW, conscious it’s never quite managed to fully clobber arch-rival Mercedes-Benz in this high-end luxury saloon class, has upped its game. This car squeezes in a massive 6.6-litre V12 engine producing no less than 610hp. Take that, meek 530hp Mercedes-Maybach S600 – and what’s with your £170K price tag? You’re making this BMW look almost a bargain.

Don’t be misled by the ‘M’ moniker here, though. This isn’t an M7. Rather, It’s an M Performance BMW, the next step down, which aims to combine a few M thrills with more well-rounded Autobahn-devouring abilities. Duly proven by BMW on the Palm Springs launch event by… starting us out on a race track.

Perhaps unsurprisingly, this isn’t the car’s natural environment. The brakes of this 2.2-tonne monster wilt after a couple of laps and, next time around, a warning light flashes up saying the engine’s overheating. Whoops.

Cornering is also dominated by understeer, and there’s just the merest hint of playfulness if you turn off the stability systems and chuck it around like an M4. The most revealing bit is actually weaving through a slalom to test out the different settings of the Executive Drive Pro roll-control suspension.

Again, in Comfort, it wallows. But in Sport, the electro-mechanical anti-roll bars kick in, and the suspension stiffens. You can now feel the effect of the rear-wheel steering and sharp control suddenly emerges. The difference is huge and proves what you can do with technology.

What you shouldn’t do with technology is use it to pipe artificial engine noise into the car, though. BMW does this, and it’s not very nice. It sounds best from the outside, where it’s pure V12: inside, the so-called Active Sound Design noise amplification just doesn’t float our boat.

Time to waft along some more authentically grotty American roads to calm down. That V12 fades into the background and the M760Li shows tremendous authority and perfect isolation. It’s brilliantly well isolated and feels all ready to devour a coast-to-coast charge.

Cleverly, the sat nav is one step ahead of you. This BMW reads the road ahead and, thanks to an Adaptive mode, will monitor your driving style to make sure the car is always in the right mode to please you. If you’re stuck behind a slow-moving car, it switches to Comfort. Seconds after you pull out to overtake, it will be back in Sport mode. It’s ingenious.

Unlike on track, it’s a more authentic sporting performer on the road. Indeed, it copes much better than an S-Class or Bentley Flying Spur would, more like a 5 Series sized car. The rear-wheel steering helps it shrink around you and a modicum of feedback encourages to you make the most of the V12’s seamless response. xDrive all-wheel drive keeps things secure when you or the road surface become too excitable.

BMW almost forgot to show us what it’s like in the back. Only the final leg back to Palm Springs gave us the opportunity to sample the tremendous rear seats, which massage you, keep you entertained with neatly-integrated Samsung tablets, treat you like true captains of industry. No matter how well it drives and how fast it is, it’s understandable why so many owners may rarely sample all this…

BMW M760Li xDRIVE

Engine: 6,592cc V12 twin-turbo

Transmission: 8-speed automatic, xDrive variable AWD, rear-wheel steering

Power (hp): 610@5,500rpm

Torque (lb ft): 590@1,500rpm

0-62mph: 3.7sec

Top speed: 155mph (limited; 189mph limited with optional M Driver's Package)

Weight: 2,255kg (EU with driver)

MPG: 22.4 (NEDC combined)

CO2: 294g/km

Price: £132,310