5. With the stock trunk floor out of the way, mock the replacement piece into position to check for fitment and trim the panel where necessary. The DSE trunk floor is one beefy hunk of 14-gauge steel that doubles as the crossmember for the coilovers. Not only does it substantially increase the structural rigidity of the chassis, but it also eliminates the need to weld a tubular crossmember to the factory framerails. In contrast, most factory floorpans are built from much thinner 18- to 20-gauge steel.