Skunk2 Racing's Pro-ST Coilovers for 1989-2005 Mazda Miata NA/NB are engineered as the best single adjustable suspension system on the market at a price point you can afford! Serious club racers and discerning high performance street car owners agree that the Pro-ST's 12 way dampening, mono-tube design, threaded shock bodies with independent height/ spring pre-load adjustment, and billet radial bearing upper camber mounts give them all the control they need at the track without sacrificing ride quality on the street. FEATURES: Mono-Tube Design 12-Way Adjustable Dampening One-Piece Forged Shock Body Micro-Polished Oversized Piston Shaft Independent Pre-Load/ Ride-Height Adjustments Reduced Shaft Stroke for Full Suspension Travel on Lowered Vehicles Billet Aluminum Spring Perches CNC Wound SAE9254V Racing Springs Spring Rates (Front/Rear): 8 kg/mm / 6kg/mm Notes: 2001-2005 Mazda Miata Installation will REQUIRE modification to the front upper A-arm or replacement with '99-'00 upper A-arm.