This is a remix of several designs, but it is based primarily on the design I tagged as the remix. To see the primary issue it resolves, please refer to the original design. This version includes a built-in filament guide and is compatible with Lulzbot's new "Beefy" Idler, which I have uploaded a remix of. I have also removed the original built-in supports.
I have uploaded two versions of the design - one for heat-set inserts, the other for the original nuts. I highly recommend the heat-set insert version as the nuts tend to strip out, or worse, cause the extruder to split.
If you choose to implement this modification, you will need to print either of the extruder bodies and one spacer. I'd also recommend printing the "Beefy" Idler - use the one I uploaded if you go with heat-set inserts, you will thank me later. You will also need one M3 x 60mm bolt and, optionally, two M4 x 4.7mm heat-set inserts.
Important note- during assembly, take note of the alignment of the Hobbed bolt. Use washers to correctly align the Hob with the filament's path.