Complete Rod, stepper, and Flat bed support system for stiffer Z setup.
To install you will need 24 - M4 x 10 screws and 24 M4 - 2020 T-Nuts, 4 - 8mm x 16mm or somthing simular for the two holes next to the lead screw to clamp it together to the flat plate in the middle.
I also suggest getting M3 x 45 screws to secure the z steppers. the factory lengths grabs but I cant imagine there is much holding it.
I printed these at .2 layers, 20% infill, and 3 wall layers and they are quite solid. On the bottom mount I printed it at 5 top and bottom layers also and that forces the thin middle part to be a solid piece of plastic. Your call on weather you do or not.
You can use this without the bottom stepper stiffners, and use the factory bolts. I run a timing belt between the steppers to sync them and didnt want them to have any play though.
Edit, if your running a belt between steppers and use this z system with the pullies on the steppers this should fit just right.
Update, Added a second top support with a larger middle hole, It was pointed that if you have a bad bow in the lead screw it will still rub in the hole and create a simular issue as the old bearing did.