Alpina has decided to boost the B5 Bi-Turbo, which is basically a tuned 550i F10 5-Series tuned to the max. The Alpina version was already a powerful beast, delivering 500 hp instead of the stock 407, but now the 4.4-liter V8 is doing what any tuned engine is supposed to: challenge the next more powerful version of the car, in this case the M5.

Thus, Alpina has tuned the B5 to produce 540 ps (533 hp) and and 730 Nm (538 lb-ft) of torque.

As a result, the 5-Series now sprints to 100 km/h [...]

Source: autoevolution