To show off the history behind the 2009 Corvette ZR1 during our first drive at Milford, GM brought out some C4 ZR-1 'Vettes. The most interesting one was this 1990 prototype adorned in vents and scoops. Corvette commander Harlan Charles says this was a testbed for a complicated and heavy active suspension system that used hydraulics to lean the big black 'Vette into turns. Obviously, with the magnetic ride control system of today, this is an obsolete setup, but interesting nonetheless.