Adrian Newey will leave Red Bull after 18 years to join Aston Martin in March 2025, but Guenther Steiner has sent his next Formula 1 team a warning about the design legend. Hiring Newey was one of the first big bits of business that Red Bull targeted upon buying the Jaguar F1 team off Ford. Despite the Briton extending his contract for McLaren in April 2005, Newey then announced in that November that he was joining Red Bull come February 2006. Many titles later and Newey decided that it was time for a new challenge this May when the Red Bull chief technical officer confirmed he was leaving Mil…