NOTE: This is for the MK2 and NOT the MK2S. If you have the MK2S you will need a different top part. User kraq has created this one to make it compatible:
I really like the improvements made to the Mk2 of the Prusa Original i3. All in all, it's a very good product. I like to use cable chains instead of cable wraps, so these are my modifications to add them to the Mk2.
The Mk2 uses every bit of space available for the heatbed which proved a bit difficult for adding the cable chain with proper clearance. To make up for this, I added a couple of additional parts to allow the part connecting to the x carriage rotate about the z axis. My other goal was to make as minimal modifications as possible. The only parts from the kit I've replaced are the Rambo housing and heatbed cable cover. Also included in the files are a cable chain that will allow full rotation, not only in one direction. This is to be used at the end of the chain (the links nearest the x carriage and nearest the heatbed cover).
Please note: With this you will no longer be able to use the spool holder. You will need to mount it elsewhere.
You will need to measure your cable lengths. After printing 20 links (or so) you should be able to connect them and figure out how many total you will need. Based on multiple reports, people have different cable lengths on their Mk2s. Also, at some point the rambo box changed where you may need to print a new cover as well.
I printed 32 regular links + 1 full rotation link for the long chain to the extruder and 16 regular links + 1 full rotation link to the heat bed. To install the top part on the x axis carriage, remove the zip tie around the cables. This piece should fit onto the carriage. You can then reinstall a new zip tie going through the new part as well its the original path. An additional zip tie to hold the cables in place just before they enter the chain is recommended.