What is it?
It's the new Alpina B5 Biturbo, the latest creation from the BMW-based manufacturer and the first chance we’ve had to sample a 'performance' version of the new 5-series.
Recent Alpinas have avoided using the same engines as M division products, but the B5 will come pretty close to going head to head with the forthcoming M5. It shares the same basic 4.4-litre V8 engine (the inlet set-up is different), equipped with two retuned turbochargers.
In Alpina tune the unit produces a flat 500bhp and 516lb ft. That's enough, says the firm, to take the car from 0-62mph in 4.7sec and onto a gloriously unrestricted 191mph.
Unlike the M5, which is likely to use a dual-clutch transmission, the B5 gets an eight-speed automatic. But the unit has been developed by Alpina and ZF, and it uses a trick way of speeding up shifts when you're in one of the car's sportier modes.
Instead of merely retarding the engine timing, the B5 uses its direct injection tech to merely cut off a cylinder or two. Alpina says the system cuts gearshift times in two, to around 180ms.
What's it like?
Jaw-droppingly fast. We drove the B5 from Alpina's base in Buchloe to the UK - in time for its appearance at the Goodwood Festival of Speed - and with an empty stretch of autobahn in front of it, it's supercar quick.