[Video] Super-saloon showdown: 2018 BMW M5 vs Alpina B5

The BMW M5 is typically the benchmark big German super-saloon. Its twin-turbocharged engine makes all but 600bhp these days, and drives all four wheels of the hottest BMW 5-Series, to make it a crushingly capable sedan. But, as Yoda once said: there is another. Alpina is an independent manufacturer and valued customer of BMW, and as soon as an M-car is on the horizon, so too is the Alpina version. This is the B5, equal on power with the M5 and also employing four-wheel drive, but with a very different, rather smoother and more discreet way of going about, ultimately, the same job. Which is the best at it?