The 2mm coated aluminum spacer fits beneath the differential and slots/keys toward framework. You can spot 2 alongside eachother to generate 4mm spacer. The style is manufactured such method your 2 spacers will freeze place. According to the meals use you may want to furthermore spot out of the right back stiffener. Increasing the rollcenter goes the differential greater aswell, creating more grip and steering, but less easy to drive.