"Which hardware kit do I need for my printer?"
The first thing to look at is the multi-material system you have. For MMU3* you need the rewinder versions, for INDX the SpoolRollers are neccessary. Then choose the "Single-Story" for the 4-tool version, or the "Double-Story" for the 8-tool version.
The digital files packages always include files for all configurations, and the kits are complete for the maximum amount of supported spools.
* For MMU3, it is not advised to put INBXX below or aside the CORE one, because that will increase tube lengths signifficantly. Therefore, COREBOXX is still the generally adviced route to go.