AST Suspension 5100 Series Coilovers (Excludes Front/Rear Top Mounts) - 1988-1990 BMW M3 2.3 (E30)The 5100 Series shock absorbers for the 1988 1990 BMW M3 2. 3 (E30) 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. With the 5100 Series suspension you can