With its twin-turbo 4.4-liter V8 producing 530 horsepower and 553 lb-ft of torque, the standard BMW M850i is no slouch. Manhart clearly disagrees, however. The German tuner previewed its upcoming tuning package for the 8 Series Coupe last year, but now we have full details and photos of the monster M850i to marvel at.

Under the hood, Manhart has tuned the M850i's 4.4-liter twin-turbo V8 to produce 621 horsepower and 656 pound-feet of torque. That's significantly more power than the stock M850i, and even more horsepower than the range-topping M8 Competition, which has 617 hp and 553 lb-ft of torque on tap.

Like the standard car, power is sent through an eight-speed automatic transmission. Manhart hasn't said how this substantial power upgrade has affected the performance, but the acceleration should be similar to the M8 Competition, which can hit 0-62 mph in 3.2 seconds. Top speed is also limited to 189 mph in the M8 Competition with the M Driver's package installed.

To complement the engine upgrade, Manhart has also modified the exterior to give the BMW M850i a meaner look. Among the carbon-fiber components added include a front splitter, diffuser, mirror caps, and a rear spoiler.

Manhart's 8 Series Coupe is also finished in black with a contrasting golden stripe and sits on 21-inch matte black alloys with a six double-spoke design. An H&R set of springs bring the car around 1.18 inches closer to the ground, giving it a sportier stance. Changes to the cabin appear to be minimal, apart from some custom Manhart badging on the center console.

Manhart hasn't revealed how much its upgraded M850i will cost. In the US, the standard BMW 850i coupe starts at $111,900, whereas the range-topping M8 Competition will set you back $146,000.