The Porsche 911 came equipped from the factory for high performance cornering -- but some things have changed in the almost 40 years the 911 has been on the road. For one, the rubber suspension bushings that monoballs replace are most likely already worn out or cracked from decades of use.

Why not replace them with stock rubber bushings? Most 911 owners today, especially those of us who take our cars to the track, have equipped our Porsches with tires much wider and stickier than stock, which allows higher g-forces to be achieved in cornering and braking. During that type of hard driving, rubber suspension bushings are compressed and flexed by the extreme loads being put on them, defeating your car 's finely tuned alignment settings, thereby reducing your braking and cornering potential.

Rennline monoballs are cadmium-plated and come with specialized tools and detailed instructions to allow a simple and quick installation (other brands require large socket and wrench sizes to torque the front monoballs, requiring additional tool purchases).