The Wisefab BMW E9x M Rear Suspension Arm/Hub Knuckle Kit offers the completely revised kinematics and roll centre for ultimate grip / traction, along with dual rear caliper mounts so you can us a completely independent hydraulic handbrake.
As you can probably tell from the images, this kit is a bit of a work of art! It's fair to say that if you are using an E9X chassis in competition, this is one of the best alterations you can make.
Please note: This kit is not compatible with an E9x non-M rear subframe. We have a non-M specific version listed here on our store