Here is one of the Time attack/Superlap Battle cars we're building at Designcraft. This car (2009 STi) will be competing in the street and limited classes. The client ordered a Pro Drive dry carbon WRC spoiler. Since this is meant for a race car, the mount for it goes through the rear glass... Or poly carbonate. This car will be competing in street class so the use of polycarbonate windows is illegal... And we couldn't drill the tempered glass Heres how we did the mounts. Hand shaped .063" aluminum.