In September 2005, at the IAA motorshow, Alpina introduced the E63 B6. As BMW launched the M6 Coupe at the same motorshow, Alpina presented the B6 in Cabrio version.

In September 2007, at the IAA motorshow, Alpina presented the updated, even faster B6 S with 530 bhp and 725 Nm.

The B6 uses the same supercharged V8-engine as the E65 B7, also called the H1. This engine is based on BMW´s 4,4 litre unit, found in the 545i and the 745i. In standard version it produces 333 bhp, in Alpina´s version it delivers 500 bhp. Please refer to the E65 B7 section for more information about this engine. A limited slip differential is standard.

From March 2007, the B6 has a new generation 6-speed gearbox, which shifts considerably faster.

The suspension has been uprated with 20mm lower, stiffer springs and modified dampers. The B6 has specially developed Michelin Pilot Sport 2 tyres, 255/35 ZR20 at the front and 285/30 ZR20 at the rear. The same brake set-up as the E65 B7 is used, which comes from the BMW 760 Li. The front disks measure 374/36mm and the rear disks are 370/24mm.

Inside the B6 is equipped with sport seats in Alpina design leather, new instruments with blue background and red needles, luxury wood “Myrtle”, a hand-stitched leather steering-wheel, Alpina floor mats, Alpina door sills and a silver-plated production plaque. The exterior changes are very subtle, front and rear spoiler lips are fitted. These make the car more stable at speed while maintaining a very low CW-value. The B6 also has four large exhaust pipes, which are very easy to notice.

For the B6 Coupe, Alpina claimed a 0-100 km/h time of 4,6 seconds. At first Alpina mentioned having to limit the top-speed to 300 km/h due to tire issues, however fortunately these were resolved. The B6 Coupe is unlimited and capable of 315 km/h.