Madness billet aluminum flywheels are CNC machined and exceed SFI standards for high stress racing applications. These units are recommended for highly modified street or racing vehicles, and for mildly modified street cars that can benefit from reduced rotating mass without the loss of daily drivability. The body of the flywheel is made of tempered aluminum 6061 T6 for ultimate strength and lightest possible weight. The 1/4 inch thick friction plate is a 1050 high carbon alloy, for incredible durability with any friction disc material, even iron. The plates are secured to the body by aerospace fasteners or stainless steel rivets, depending on the application. These fasteners were chosen because of their exceptional strength and corrosion resistance. The ring gears are pressed on and secured with grade 10 fasteners. The gear is also heat treated for longevity. They are effective, durable and almost too pretty to install! Cooper Factory Dual Mass Flywheel weighs 18lbs. Lightweight flywheel weighs 10.5lbs. Transmission removal is required to install this product so while you're in there, why not consider one of our Performance Packages which includes a high performance clutch? Your cost savings in labor would equal roughly $1000 if you ever planned to install one of these in the future.