Port Elizabeth - It's not every day you get to drive a luxury limousine around a racetrack, but the newly launched BMW M760Li xDrive priced at R2.7-million is no regular luxury limo.

The ever-playful engineers at BMW's M division have given this car the high-performance 6.6-litre TwinPower turbo V12 treatment and created not only the most powerful BMW production car yet built, but also the quickest accelerating one.

Pampered executives with a sporty streak will be pleased to know this lusty limo whisks from rest to 100km/h in just 3.7 seconds, quicker even than more overtly fire-breathing BMWs like the M5 and M4, and placing this 'super seven' into the accelerative league of cars with horses and bulls on their badges. With an optional M Driver's package, the 250km/h restricted top speed is raised to a governed 305km/h – ungoverned it would probably be fast enough to compete in the Indy 500.

BMW South Africa last week hosted the car's media launch at Port Elizabeth's Aldo Scribante racetrack, on what is the 40th anniversary of the 7 Series in this country. The first V12-engined version, the 750i, came along in 1987 wielding 220kW of normally-aspirated 5-litre power with rear wheel drive and hit the 100km/h mark in 7.4 seconds. It was a mighty feat for the time but the modern 7 Series flagship goes into true supercar territory with its sub four-second sprint and outputs of 448kW and 800Nm, with all-wheel drive to better manage all the muscle.

When you punch the accelerator the car explodes into silky aggression as g-forces pummel you into your luxury leather-padded seat. The rampant power feels out of synch with the silky smooth reverie of the soundproofed cockpit, which filters out all noises save for one: the fairly lusty growl of that V12. Kudos to the M-gineers for not making it sound like a sewing machine.

This hefty 2.3 ton car will never be a track machine, which is why BMW shied away from calling it an M7, but it does hold the road remarkably well for its size and there are M-specific styling, chassis and technology touches to give the M760Li xDrive a more athletic character. The eight-speed automatic has received M Performance-specific tuning to deliver more instantaneous downshifts, while the xDrive is a rear-biased all-wheel drive system that prevents early understeer.

Integral Active Steering adjusts the angle of the rear wheels to reduce low-speed steering effort and improve high-speed stability, and active roll stabilisation prevents the big car from wallowing in the corners without affecting the silky ride comfort. Gripping the tar gamely are performance tyres fitted to exclusive matt grey 20" wheels, while the 19-inch M Sport brakes dealt with the rigours of track work without fading.

The idea of a sporty 7 Series goes back a long way. The legendary Winfield-sponsored 745i that was raced here in the eighties by the equally legendary late Tony Viana kickstarted the whole thing. Built as a South African special to take on the mighty Alfa GTVs and Sierra XR8s of the time, the near-standard 745i was driven by Tony to victory in the 1985 Group 1 championship. Today the restored car is raced in historics by Tony's old team-mate and friend Paolo Cavalieri.