In 1991 it was possible to order right from the dealership a Callaway Twin Turbo package for the new C4 Corvette.
Twin intercooled turbochargers and revised engine management added 150 horsepower, raising output to 403 hp.
All conversions were difficult to acquire due to their low production numbers, the most notable was the Series 1 Speedster, which was limited to ten units.
Just recently number 8 of 10 produced was auctioned at Bloomington Gold Corvette auction for $115,000. This silver Series 1 Callaway Speedster used to be part of the Otis Chandler collection before being acquired by Chevrolet dealer and Corvette collector Bob McDorman.
This Twin-turbo Corvette Callaway Speedster featured cut-down windshields, silver Calaway Aero body, wraparound glass, special OZ wheels, unique Wedgewood blue Speedster interior and twin integrated headrests.
via: corvetteblogger
