At the moment, BMW is still in the middle of developing the all-new M5. While it might be a while before the new M5 debuts, longtime BMW tuning house Alpina has just unveiled the most powerful 5 Series available in the meantime. Dubbed the B5 Bi-Turbo, it is available in both sedan and wagon guises.

Geneva 2017: All-new BMW 5 Series gets the Alpina treatment

Powering the Alpina B5 Bi-Turbo is BMW's 4.4-liter TwinPower Turbo V8 engine. Modified by the company, it puts out 607 PS and 800 Nm of torque. It trumps the car it's based on, the BMW M550i xDrive, by 145 PS and 150 Nm. An eight-speed sport automatic is the lone transmission choice for the super sedan and it lays down its power through xDrive all-wheel drive.

Alpina claims the B5 Bi-Turbo sedan can do 0 to 100 km/h in 3.5 seconds while the heavier wagon variant does the same task in 3.6 seconds. Other performance upgrades include a re-tuned suspension, bigger brakes, uprated exhaust system and the deletion of the speed limiter. Without the limiter, the sedan has a top speed of 330 km/h while the Touring is maxed out at 325 km/h.

Alpina B5 Bi-Turbo Touring

In Alpina tradition, the tuning house added their own touches to separate their models from standard BMWs. The body is unchanged from the sedan and wagon variants of the 5 Series but the Alpina gets its own body kit. With this kit, the front apron integrates a cooling duct on each side and at the center is Alpina lettering, the firm's tradition since the 70's.

On to its side, no significant changes were made for the B5 Bi-Turbo, save for the air outlet trim being finished in gloss black. Towards the rear, it gets a variation of the BMW M Sport bumper but Alpina added a diffuser at the bottom. It is then finished off with the tuning firm's own deck spoiler. Both the sedan and wagon ride on newly-designed 20-inch alloy wheels.

Alpina B5 Bi-Turbo interior

Inside, it is the same as the regular 5 Series models save for Alpina's individual touches. Both sedan and wagon get an Alpina-designed steering wheel, full Nappa leather seats and trimmings, wide selection of interior colors, piano black wood trim with Alpina inlays, illuminated door sills and an individual production plaque.