G-Power GP-620 Boosts BMW M850i to 620 PS, 186 mph

G-Power has released a GP-620 upgrade for the BMW M850i xDrive that raises peak output to 620 metric horsepower and claims a 186 mph top speed. The tuner published images and specs for the project on its social channels, showing both the powertrain package and a range of exterior and interior upgrades.

Powertrain packages and pricing

The GP-620 bundle is rated at 620 hp (612 bhp / 456 kW) and 627 lb-ft (850 Nm) of torque, and G-Power lists a maximum speed of 186 mph (300 kph). G-Power also offers a more extreme GP-670 upgrade: that package is reported as 661 hp (670 PS / 493 kW) with 664 lb-ft (900 Nm) of torque. G-Power’s stated price for the GP-670 bundle is €13,014.99, while the GP-620 is listed at €2,495.

BMW’s factory M850i is specified at 523 hp (530 PS / 390 kW) and 553 lb-ft (750 Nm) from its 4.4-liter twin-turbo V8, and the standard factory 0–62 mph time is 3.7 seconds. G-Power has not published official 0–62 mph or 0–100 kph times for the GP-620 or GP-670 at the time of publication.

Body, wheels and interior options

The car pictured with the GP-620 package also shows several G-Power visual and hardware upgrades. These include a Venturi carbon-fiber bonnet, a GP-Dynamic carbon-fiber rear wing, Hurricane RS 21-inch forged wheels and a rear silencer with four carbon tailpipes. G-Power’s catalog for the 8 Series additionally lists a front splitter, side flaps, a coil-over spring set, alternative wheel options, a new steering wheel with aftermarket paddle shifters, velour floor mats and the possibility of a full interior makeover.

G-Power notes that many of these parts fit other 8 Series variants, not only the M850i. For the 840i, the tuner offers two powertrain upgrades: the GP-450, rated at 444 hp (450 PS / 331 kW) and 457 lb-ft (620 Nm) for €4,932, and the GP-400, rated at 395 hp (400 PS / 294 kW) and 428 lb-ft (580 Nm) for €1,995. BMW’s standard 840i and 840i xDrive use the B58 3.0-liter turbocharged straight-six, listed at 335 hp (340 PS / 250 kW) and 332 lb-ft (450 Nm); factory 0–62 mph times are 5.3 seconds for the rear-wheel-drive car and 4.9 seconds for the xDrive version.

G-Power’s portfolio also covers other models in the M8 lineup, including coupe, convertible and Gran Coupe body styles. The tuner shared the M850i project details and imagery in a social media post; the report above is based on that material and on the factory specifications that G-Power referenced.