E36/E46 Ballast PlatesGSR E36 46 ballast plates, the Base Plates bolt into the factory passenger side seat mount crossmembers. Plate extends rearward of the rear seat bolt holes approximately 7", and plate extends forward of the front seat bolt holes approximately 3". Additional Top Plates can be stacked on top of these to achieve your desired ballast weight. Nuts are partially captured on the bottom to keep from spinning during torquing of upper plates to base plate. M10