This might come as a bit of a surprise, but we should remind you it's been nearly four years ago since Mercedes-AMG unveiled its F1-derived hypercar dubbed Project One. Yes, it debuted back in September 2017 at the Frankfurt Motor Show and the folks from Affalterbach have yet to deliver a customer car. On its bumpy road to production, the hybrid V6 machine has lost "Project" from its name and has now been spotted during final testing.

Several prototypes were caught on camera near and at the Nürburgring, tackling several weather conditions varying from sunny to even snowy. It really does sound like a Formula 1 car, and while it's no naturally aspirated V12 from the golden era of the early 1990s, the turbocharged hybrid 1.6-liter V6 does make some alluring noises.

Gallery: Mercedes-AMG One Nurburgring Spy Photos

If you're wondering why the prototypes are still camouflaged, it could be because the final version has gone through some aero tweaks Mercedes-AMG doesn't want to reveal just yet. It's the same reason why one of the test vehicles has a special livery signaling the E Performance branding reserved for performance-oriented hybrids and EVs.

The AMG One's development has had its ups and downs, but that's to be expected when you're adapting a fragile and extremely complicated Formula 1 engine for a road car. As a refresher, the six-cylinder engine will have to be rebuilt once every 50,000 kilometers (31,069 miles). Chances are that's unlikely to be a big issue since these hypercars are rarely going to be driven that much given their exclusivity as only 275 units are planned.

Combining the V6 with no fewer than four electric motors will result in a total output of over 1,000 horsepower. The combustion engine is expected to rev at up to 11,000 rpm and help the all-wheel-drive hypercar reach a maximum speed of over 217 mph (350 km/h). It goes without saying AMG will fix all issues it stumbled upon during development, including achieving the idle engine speed of around 1,200 rpm (down from the F1 car's 5,000 rpm) and making the powertrain meet the stringent WLTP emissions standards.

It's understandable why some of the hype around the AMG One is gone as the road to production has been extremely long, but we're still genuinely excited to see the final car. Customer deliveries of the $2.7-million machine are scheduled to commence before the end of 2021, which means the official premiere should take place in the coming months.

Another ultra-fast AMG hybrid is planned for this year – the GT73e with a little over 800 horsepower from a PHEV V8 setup.

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