Isdera Imperator 108i

The CW311 was Schulz's answer to two Mercedes cars he loved: the 300 SL for the doors, and the C111 research cars for the wedge. Its drag coefficient of 0.311 gave the concept its name. What is remarkable is how little of it he had to change to sell it. The production Imperator lost the pop-up headlamps for fixed units and took Mercedes tail lights, and that was largely that until 1991, when the facelift put the pop-ups back and rounded the surfaces. The signature is the roof. The periscope bulge sits above the cabin like a fin, and it exists because Schulz wanted the rear view without the drag and visual clutter of door mirrors. Inside, the switchgear and much of the trim comes from the Porsche 928, which is the tell that this was an engineer's car built from the best parts he could reach rather than a stylist's clean sheet. Nothing about the shape is fashionable now. It was not fashionable in 1984 either. It was a 1978 drawing, built stubbornly, for nine years.

Isdera never raced the Imperator, and the reason is arithmetic rather than temperament. The R in the company name stands for racing, and Schulz came out of Porsche, but a firm turning out three or four cars a year has no budget for a homologation programme and nothing to gain from one when every customer is already known by name. The lineage is more interesting than a results table. The shape descends from the Mercedes C111 research cars, which is a genuine competition bloodline: the C111 series ended with high-speed record running at Nardo in 1979, and the CW311 that became the Imperator appears in the C111 story as one of the things that came after it. The engines have their own record too, since the M117 and its AMG derivatives were the Mercedes V8s that AMG had been campaigning in European touring cars. So the car carries racing DNA at one remove, through the parts and through the shape, and never turned a competitive lap itself. For thirty hand-built cars sold to people who telephoned the factory, that was never the point.

The Imperator's cultural footprint is small, specific and oddly durable. The 1978 CW311 that started it all appeared in the 1980 comedy Car-napping, which is the only time any version of this car reached a mass audience. After that it disappeared into the back pages of the supercar books, the car everyone half-remembered as a Mercedes that Mercedes never made. The internet gave it a second life. Road and Track ran it in 2016 as a Mercedes-Benz wedge from the future. Car and Driver covered a car for sale the same year under the headline Down Periscope. Hagerty came back to it in 2021. The pattern is always the same: a writer discovers the periscope, the gullwing doors and the story of Schulz and Mercedes, and the piece writes itself. Two of the thirty were reportedly exported to Japan, which is where a good number of Europe's stranger 1980s supercars ended up and where the model retains a following. Nobody has ever put an Imperator on a bedroom wall in numbers. It is a connoisseur's car, known by the people who know it.

Owning one is an exercise in knowing which half of the car you are dealing with. The Mercedes half is dependable and unremarkable, which is exactly why Schulz used it: the V8s are long-lived, the ZF gearbox is tough, and the running gear is period Stuttgart engineering that nobody needs to be frightened of. The Isdera half is where the effort goes. Every panel is bespoke fibreglass, the periscope and its housing exist on no other car, and the gullwing struts and seals are one-offs. None of it is unfixable, but all of it means fabrication rather than ordering a part, so plan work around long lead times. The cabin gets warm, as it does in most mid-engined cars of the era with a big V8 and a low glasshouse. Rear vision through a single periscope image takes practice. And factory support is not what it was: the German company has changed hands more than once and the entity that built these cars is long gone, so the knowledge lives with a small number of specialists in Germany rather than with the marque.