Westland, Michigan-based Rehagen Racing competes in the Grand American Road Racing Association's KONI Challenge Series GS Class. Full-time employees of Ford Motor Company or Roush Industries and led by Larry Rehagen, the team devote much of their free time to their on-track success.

The 2006 season was highlighted by a 6th place finish at Laguna Seca and back-to-back Top 5s at Barber Motorsports Park (2nd) and Trois-Rivieres (4th). Driver Ray Mason and the #59 2005 Mustang GT both finished 11th in the 2006 Standings--higher than any other Mustang in Grand-Am Cup.