Earlier this year, BMW introduced a higher-performing CS version of the M3 to kick things up a notch with extra power and carbon fiber along with other tweaks. Despite its many upgrades, it looks tame when you compare it to this wild custom build carrying the “GT4” moniker. It used to be an Isle of Man Green G80 before the owner turned it into the ultimate sedan.

The high-performance saloon features a full body wrap that takes inspiration from BMW’s own M4 GT3 and GT4 race cars. It has an impressively long list of mods that includes everything from a body kit and forged lightweight wheels to a rear wing and yellow daytime running lights. It’s not all show without any extra go as the S58 engine has been fully built with hybrid turbos and other changes that have boosted output to an enormous 900 hp at the wheels.

BMW M3 GT4 custom build / g80_soom

You can find the full list with mods at the source link below. Perhaps the most interesting feature of this car is the six-speed manual, because yes, this is a rear-wheel-drive car with a clutch pedal. It must be a real hoot to drive given the absurd amount of power going exclusively to the rear axle, although we’d reckon it’s quite a bit intimidating given its tail-happy nature.

It’s safe to say BMW will never make the M3 as extreme as this custom build, which is why the aftermarket scene is always happy to deliver. A substantially different M3 is in the making back at home in Munich where work is underway for an officially confirmed electric high-performance sedan. It won’t spell the end of the gasoline-fueled variant, so tuners can rest assured the twin-turbo 3.0-liter engine is not being retired anytime soon. In fact, the M division has pledged to keep the inline-six and V8 until at least 2030.

In the meantime, spy shots have revealed BMW is working on a Life Cycle Impulse for the M3. It’s slated to arrive in 2024 when the M3 Touring and M4 Coupe/Convertible are likely to get the LCI treatment as well.

Source: g80_soom / Instagram