The Horch’s darkness cast a chill over the sunny field, a relic of its grisly past. Looking shockingly out of place among sparkling restorations, Jim Taylor showed this 1937 Horch 853 Cabriolet in the Pebble Beach Concours’s Preservation Class.

Back in 2006, the dusty black convertible sold for $299,000. And was described in RM Auctions’s catalog as “a very sound original”, showing fewer than 36,000 miles. It still carried its 1953 U.S. Forces in Germany license plate. Under the back seat, the Stevens family, who were selling patriarch J.C.’s estate, discovered some of its sinister past in the form of a WWII Wehrmacht-issue automatic Luger featuring an SS stamp.

Just one of 80 lots in the RM sale, it was probably the most interesting one. Captain Harold Young returned to the U.S. from serving in Germany and traded the Horch for a year-old Buick. The dealer, presumably J.C. Stevens, stored it in 1955.

Most mainstream collectors largely shun Nazi memorabilia. But the Horch is a historical artifact, and its grotesque reality is inescapable. A restoration could never cleanse whatever crimes it ‘witnessed’, posing an increasingly relevant question to the car-collecting world. When should you restore a car, and when should you preserve it?

While not nearly as famous as Mercedes-Benz, Horch is almost as old, being founded by August Horch in 1899, after working for Benz for three years. After being fired by his company’s board in 1909, Horch started Audi, which is the Latin verb meaning to listen – the same meaning as Horch in German. In 1932, Horch, Audi, Wanderer and DKW merged, forming Auto Union. This merger left August Horch atop his old firm as well.

Well-known for building quality automobiles, Horch set his sights on the Mercedes-Benz market, with OHC 4.5-liter straight-eight engines, and even a 6-liter V-12. However, Mercedes-Benz persevered with superchargers and Horch did not, leaving his elegant cabriolets relatively underpowered, with a top speed around 90 mph. But the elegant 853 series was visually comparable with the Mercedes-Benz 500K and 540K series.

A number of the 400 model 853s built between 1936-1940 were also custom bodied. Horch was recognized as a marque at Pebble Beach in 1999, and two restored Horches have won Best of Show: An Erdmann & Rossi Cabriolet in 2004, and a Voll & Ruhrbeck Sport Cabriolet in 2009.

Guy Mace of Springfield Ohio owns a 1936 Horch 853 cabriolet, probably from the same group of 60 cars built for the Wehrmacht, with a pennant holder on the front fender. He bought his car in 2010 at a Cox auction at Branson, Missouri, still covered in dust from years in a South Dakota garage.

Horch won a Wehrmacht contract to supply 60 staff cars in 1936 and ‘37. Both of these cars were apparently part of that group. Hitler (who owned no cars himself) was partial to the Mercedes-Benz Grosser 770K, but other top Nazis like Goering and Himmler liked the elegant Horches. Needless to say, original paperwork was hard to come by after WWII. American officers bought many such cars straight out of the motor pool, as modern cars, without gruesome connections, replaced these Nazi-mobiles.

Mace’s car was one such Allied motor-pool car, and was also shipped stateside in the 1950s. It was displayed in a museum in St Louis, Missouri for several years, then went to another museum in Rapid City, South Dakota. Driven occasionally in parades, the cabriolet was sold to a local businessman when the museum closed. The car’s last recorded outing was in the mid 1970s when it participated in the Black Hills Auto Show. Its longtime owner died in 2010, and the car was sold at Branson, where Mace bought it.

“It was the Holy Grail of collector cars – in storage for 50 years, muddy and dirty” he said. “It would be worth two or three times as much if I’d restored it, but I’m not in it for the money. It’s about the love of cars, and an interest in antiques.” Mace fitted new tires, checked the brakes and entered his car in Pebble Beach’s Preservation Class in 2015.

“I kept it for two or three years and didn’t really know what to do with it,” said Mace, who has a large car collection. “I decided to enter it in the preservation class at Pebble Beach, but nobody knew how to prepare a car for that, so I had to look it up. I knew all the gauges had to work, so I repaired one that didn’t, bought some new tires, fixed the brakes and serviced the car.”

Mace found an excellent compromise to maintain the original integrity of his car through conservation. The Horch had received a poor-quality black paint job in the 1950s, but Mace discovered that its original finish lurked underneath, in quite good condition. He wet-sanded the car, and revived its striking original appearance, while preserving its patina.

In both cases these cars vividly illustrate their past in a way that would have been irretrievably lost through restoration. As expert collector Miles Collier observed, “An antique must show evidence of the passage of time.”