Yeah a few tech things give away the chassis designation like the damper change over, brake duct configuration, etc…biggest thing though are the drivers names on the side of the monocoque :lol Schlesser/Mass car is C9 chassis number 5, the drivers that dominated in '89 to early 90. Wendlinger eventually ran in a C11 in '91(the picture John posted is a C11, not a C9)
I miss GTP/G-C 