When it comes to aftermarket tuning, BMW convertibles rarely receive the same level of attention as their coupe, sedan, or Touring counterparts. More often than not, tuners focus their energy on hardtops, leaving the open-air models somewhat overlooked. This lack of attention, however, has created the perfect opportunity for G-Power, a German tuning house known for its extreme builds, to showcase its latest project. The result is a heavily modified BMW M4 Convertible, rebranded as the G4M Bi-Turbo Convertible, and it’s a machine that pushes the droptop well into supercar territory.
The transformation goes far beyond the usual bump in horsepower. G-Power has turned to lightweight carbon fiber components to both enhance performance and give the car a more aggressive appearance. At the front, an all-new vented hood made from carbon fiber improves cooling for the engine bay while adding a race-inspired look. Underneath, the engine is topped with a unique carbon fiber engine cover, highlighted with striking orange carbon accents for extra flair. More carbon can be found on the redesigned front bumper and grille, the latter styled to resemble the performance-oriented grille of the M4 CS. Completing the exterior changes are a set of Hurricane RR forged wheels, measuring 21×9 inches at the front and 21×10.5 inches at the rear, giving the convertible a more muscular stance.
Of course, the real centerpiece of this build lies under the hood. The tuner has fitted a carbon fiber air intake system, HJS downpipes, and a new rear silencer with bespoke tailpipes, all of which allow the 3.0-liter twin-turbocharged inline-six to breathe more freely. Combined with a tailored software tune, output climbs dramatically to 700 horsepower and 850 Nm of torque. This is a huge jump from the factory figures and places the M4 Convertible firmly in the realm of exotic performance cars. While G-Power hasn’t provided official acceleration numbers, it does claim the car is now capable of reaching a top speed of 310 km/h, putting it on par with some of the world’s most celebrated supercars.
The upgrades aren’t limited to the convertible alone. G-Power has confirmed that the same engine tuning package can be applied to all other versions of the M3 and M4, giving owners of hardtops access to the same performance levels. Even the smaller BMW M2 isn’t left out, with a 700 hp kit available for those wanting to transform the compact sports car into an absolute powerhouse.
By giving the often-overlooked M4 Convertible such extensive upgrades, G-Power has created a car that not only demands attention but also challenges the notion that droptops can’t be serious performance machines.