It’s G-Power’s 600bhp BMW M4 Convertible

Things the BMW M4 needs more of: traction. Things the BMW emphatically does not need more of: power. Why do you think the racily named Competition Package is more about reining in the handling than upping the pace?

Still, a manufacturer’s power figure is merely a pathetic starting point for the world’s tuning houses to heap their own horses onto. Which brings us neatly to the near-600bhp G-Power M4 Convertible. Flipping heck.

In fairness, G-Power has been pulling huge power out of BMWs for some years now, even setting world speed records with its supercharged V10 M5s. these guys know what they’re doing.

So much so that their simple ECU remap is enough to liberate 513bhp and 516lb ft from the bi-turbo straight-six, up from 424bhp and 406lb ft out of the box.

That ought to be enough for a car with a folding hard-top roof and known traction issues, right? Pah, G-Power laughs in the face of your lily-livered sensibilities. Bigger turbos and other hardware tweaks liberate a full 592bhp and 546lb ft.

Is it fast? Yes, it is fast. How does 0-62mph in 3.7 seconds grab you? Pretty briskly, we should think, given that’s a whole 0.7sec quicker than the base car.

In the bin with the original turbo blades is the electronic speed limiter, so G-Power confidently predicts a 200mph top speed. Oof, that’s very close to the Daehler Design & Technik M4 drop-top…

Also on the menu are forged 21-inch wheels and an adjustable set of coilover suspension components. It’s a comprehensive set of upgrades for the least focused M4, then. So, this, or a BMW M4 GTS?