AST 5100 Series Coilovers | Subaru Impreza GC/GF (98-00) (ACC-S6202S)The 5100 Series shock absorbers for the 1998 2000 Subaru Impreza WRX 2. 0 GT Turbo 4WD (GC GF PCD 5x100) utilize inverted upside down technology. The inverted design is race proven technology and produces an extremely strong damper, providing better suspension geometry under heavy lateral and braking loads as seen in a road and track environment. The 5100 Series shock absorbers give your car a better performance than the standard twin tube design.