What's this then?

These are Alpinas, or as they're often described, BMW M cars for the more discerning driving enthusiast. Alpina is not your normal tuning house either - while it is an independent company, and always has been, BMW considers its work so good that it's happy to give Alpina models full factory warranties.

For its 50th birthday then, Alpina has created Edition 50 versions of its B5 and B6 - much-modified version of the 5 Series and 6 Series. The Biturbo badge on both cars refers to a heavily modified BMW 4.4-litre twin-turbo V8 engine, which has been tweaked up to 600hp and 800Nm of torque. Alpina claims that this is the most powerful engine it has ever created.

So they're a little quick?

Performance is just bonkers. The 0-62mph sprint in the B5 is done with in 4.2 seconds and it'll go on to a top speed of 203mph - or 200mph if you go for the Touring estate - and remember, BMW won't build you an M5 Touring... The B6 coupé is a fraction faster, with a top end of 205mph.

Astonishingly, driving through the standard eight-speed ZF automatic gearbox, both of these cars can almost crack 30mpg on average. Both cars get a specially designed titanium sports exhaust system, 20-inch wheels in that classic Alpina-style turbine pattern and 395mm Brembo brakes to keep all that performance in check.

What about the interior?

Inside you get Nappa leather with green and yellow accents - a tribute to the classic B7 Turbo Alpina of the eighties - and all the controls are finished in hardwearing ceramic. Only 50 of each will be built and prices start at a fairly hefty £83,862.