The 2006-2008 BMW Z4 M is fast becoming a cult classic among great M cars offering plenty of performance courtesy of a 3.2-litre inline-six and light overall weight. But Manhart Racing wanted more from its M Roadster, so out went the M3-derived S54 engine and in went a stonking-great S85 V10 from a BMW M5.

But while the contemporary E60-generation 5er got a 5.0-litre V10, the engine found under the bonnet of Manhart’s Z4 is bored out to 5.8 litres – now putting down 621 incredible brake horses. It's not the first time Manhart has swapped an S85, but it might be the most exciting iteration yet.

In celebration of the wicked Z4, YouTube channel AutoTopNL created a video featuring the demonic little roadster ripping around rural Holland. And while power and speed are all well and good, the sounds this thing emits are what make us weak in the knees. 

The S85 V10 found under the bonnet was engineered using BMW’s Formula 1 experience in the early 2000s, and as such it screams like a proper performance car. The engine’s head and block are constructed from aluminium as well, with lightweight engine internals that enable a redline of 8,250 rpm. Boring the engine and strapping it into the smaller, lighter Z4 M seems only to have opened it up more, giving it a high-rev shriek unlike anything we’ve ever heard in a roadworthy BMW.

Although the video from AutoTopNL doesn’t feature too much craziness – public roads, people – it’s still a fun romp through the Netherlands countryside, and the Z4 looks proper. In addition to the obvious V10-related enhancements, the Z4 sports a slick black and gold colour scheme. Big wheels, a removable hardtop, and revised ground effects add a little visual punch to the already handsome roadster.

While the S85 engine in the E60 M5 isn’t known for dependability, its exotic performance and lusty engine note might make up for it for some enthusiasts. We only wish we could hear it in person, roaring through this Z4 M’s exhaust pipes on a crisp spring day with the top removed. While this particular Z4 might be hard to find in the classifieds, Manhart will still happily do you a new BMW roadster (or even a Toyota Supra).

Gallery: Manhart BMW Z4 M with S85 V10 engine