- Broad Arrow will auction the prototype E39 M5 at Zoute Concours in Knokke-Heist on October 9, 2026, estimated $285,000–$400,000.
- The naturally aspirated, all-aluminum 5.0-liter W10 is rated at 473 hp.
- Only three Volkswagen W10 engines were ever built.
Only one road-going car has ever carried a Volkswagen W10 engine, and it wears an E39 BMW M5 body. Broad Arrow Auctions will offer the prototype at its Zoute Concours sale in Knokke-Heist, Belgium, on October 9, 2026, carrying an estimate of €250,000 to €350,000 (about $285,000 to $400,000).