Remember how promised a road legal with a V6 hybrid engine? If you don’t, you can be forgiven. The project was announced in 2017, and nothing much has come of it. But Mercedes is absolutely promising that the cars will in fact get delivered. Soon. In 2021.

The Project One was intended to celebrate Mercedes’ dominance in F1 by giving driving enthusiasts and/or car-collective obsessives a chance to purchase a car with the very same engine that won the team its championships. As it turns out, it’s somewhat hard to put an F1 engine in a road car and actually have it, y’know, work.

Hence the delay. Mercedes-AMG originally projected the One to be shipping out in 2019, but there have been enough setbacks to push that to 2021 as . The biggest is meeting global emissions test requirements, which mandate that cars must idly stably at 1200 rpm. The Mercedes V6, however, idles at a whopping 5000. That in itself would be tough, but then, y’know, there’s that whole ‘noise’ thing, too. Even though modern F1 powertrains are pretty quiet, they are still really fucking loud compared to a regular ol’ engine.

Who would have guessed that slapping race engine in a regular car would actually prove to be really hard! Well, , as it tried this with the F50. And also Porsche, which .

The Ferrari F50 is often remembered as a flop: it was slower than the car it replaced and for years

Today is a historic day, as all days when a new flagship Ferrari is announced are. In the line…

The Porsche Carrera GT has always been known for its screaming wail of an exhaust note, not so…

All that said, customers who can drop 2.275 million euros (around $2.5 million) on a single car are probably rich enough to comfortably wait for that car to show up a little later than expected.