Bentley’s official development program for the upcoming, highly-limited, incredibly fancy Batur is now finally done. That means that the automaker can start the hard work of building the 18 examples of the coupe that will eventually end up in customer hands.

Although Batur production is so strictly limited, it remains a real car, so Bentley had to ensure that it could handle all of the same rigors as more common models. That meant creating two test vehicles, which were known as Car Zero and Car Zero-Zero.

Together, these pre-production Baturs ran for more than 18,641 miles (30,000 km) over a combined 58 weeks of total durability work. The program included performance testing on handling tracks and at speeds of more than 200 mph (322 km/h), as well as comfort tests on rough surfaces.

Read: Bentley Showcases Customized Mulliner Batur GTs In Captivating Styles

 Bentley Can Finally Start Making Baturs For Customers Now That Development Testing Is Done

The cars were also subjected to more than 600 hours of solar loading, which amounts to the equivalent of more than five years in an Arizona desert. The 800 parts that are exclusive to the Batur were all tested for durability as well.

Although Bentley knew that the cars were being tested hard, it still had to build them to the same standards as the Baturs that it now plans to start making for customers. For example, Car Zero is finished in bespoke Purple Sector paint, that is complemented by front splitters, side skirts, and a rear diffuser that comes in a high gloss natural fiber finish.

Meanwhile, Car Zero-Zero has Marina Teal paint, and its bespoke finishes and LED headlights were put through the ringer during the durability test program. These cars reflect the enormous freedom that customers will be given to spec their Baturs. Buyers will be able to choose from old school natural fiber upholstery inside, to futuristic additive manufactured gold, and more.

The Batur is powered by a W12 engine that churns out 740 hp (552 kW/750 PS), making it the most powerful Bentley powertrain ever. It was tested over the course of 100 weeks to ensure that it could handle the demands of generating such power without breaking down.

Having now finished development, the Batur is ready to start production. Bentley and its in-house customizing department, Mulliner, will work with customers to create a completely unique vehicle, which will then take four months to complete. It expects production to run until the end of 2024.