Legendary BMW tuner Alpina celebrates its 50th birthday with a brace of exclusive limited editions.

Alpina is a unique company in the world of performance tuners. Unlike most other firms, this small outfit from Bavaria enjoys a very close relationship with the brand whose cars they work on – in this case, BMW. So close in fact, that Alpina cars are even made on the same production lines as regular BMWs, and can be serviced at BMW dealerships.

What makes an Alpina different from one of BMW’s own M models, you might ask? Well for one, they don’t have such a hardcore bent on driving dynamics despite having comparable power figures to M cars, leaning more towards luxury and cruiseability instead. Alpinas also have a very distinctive, yet subtle look thanks to some trademark styling touches, such as unique decals (Alpina calls them ”Deco Sets”), mild bodykits and massive 20-spoke rims (good luck cleaning them!).

With the anniversary Edition 50 models we have here, Alpina has taken the same recipe and turned the wick up even more. Just 50 units each of the B5 and B6 Biturbo will be made, split amongst Sedan, Touring, Coupe and Convertible variants. And unlike so many other so-called special editions from lesser brands, the changes made to this quartet go so much more than skin deep.

For starters, the cars use the same twin turbo 4.4-litre V8 as in the regular B5 and B6, but thanks to items like an optimized induction system, high-capacity fuel system and increased boost pressure, it now produces 600 hp and 800Nm, 60 hp more than before — making the Edition 50 cars the most powerful Alpinas ever. This allows the century sprint to be dispatched in 4.2 seconds, and the B6 Coupe (the fastest of the four) to hit a top speed of 330km/h.

Other mechanical refinements include a limited slip differential, 4-pot Brembo brakes with 395mm rotors, a titanium exhaust system from specialists Akrapovic (17kg lighter than a conventional steel system), and unique 20-inch rims that are now forged, instead of cast, to save a massive 15.6kg of unsprung weight.

The cars are available in Alpina Green, Alpina Blue and a special Edition 50 Sepia paintjob and can be identified by a special Edition 50 Deco Set. On the inside, the cars invoke some of Alpina’s rich heritage with an optional seat package quilted in Forest Green, with yellow and black stitching; reminiscent of the interior of the E24 635CSi-based B7S Turbo.

There is also Piano Black interior trim with ”Edition 50” lettering and company founder Burkard Bovensiepen’s signature, Edition 50 sill plates and seat emblems, and a special plaque and keyring showing each car’s production number.

The Edition 50 models are some of the most achingly desirable products ever to wear the double kidney grilles — particularly in Touring form. Sadly, no matter how much you want one, you probably won’t be able to get one, as they’ve all been snapped up. The B5 Sedan pictured here is the only unit staying in Singapore, with the other three bound for new homes around the region.