The reason why most performance enthusiasts opt to go with lightweight flywheels is because less weight on the flywheel equals less rotational mass on the engine, which means more horsepower! Because of less rotational mass, your engine will rev faster as well.
The Exedy lightweight flywheel is made from a solid one-piece billet chromoly steel. These are designed for lightly tuned racing cars for all kinds of motorsports, but could also be appropriate for street use. Exedy flyhweels are tested from 15,000-18,000 RPM, and are guaranteed not to fail to the said RPM, and are all SFI approved.