Winter spent many seasons competing in the German Interserie series, usually racing privately entered Porsches, taking the title in 1986.
He was killed a week later while driving a privately entered Ferrari 512 at an Interserie sportscar race at the Norisring in Germany.
However, during the break from Mexico City to Autopolis, Konrad had the KM-011 flown back to Europe to participate in the final Interserie round at Zeltweg.
The Kremer K8 Spyder, along with its predecessor, the CK7, were open-cockpit prototypes built by Kremer Racing for use in multiple sportscar series, such as the IMSA GT Championship, Interserie, and International Sports Racing Series.
He retired from the first and third rounds of the Interserie, held at AVUS and the Nürburgring, and he missed several races altogether, before retiring in the Siegerland and the Nürburgring rounds.
Walter Lechner Racing competed in the Interserie in the 1990s, and developed their own car in conjunction with Reynard Motorsport; the Lechner Spyder SC91.