One of the upgrades is a mounting bracket for the spool holder so that it can mount on the side of the printer. This prevents the filament from rubbing against the top of the hole where the filament feeds into the extruder and wearing it out.
Chuck (CHEP on YouTube) remixed an existing Thing on Thingiverse so that you don't have to buy any additional screws. You simply need what came with your printer. However, Chuck's remix left the unused screw holes in the model. My OCD kicked in and I decided to remix Chuck's remix to fill them in so that the surfaces are smooth.
Chuck's remix on Thingiverse with unused screw holes exposed.
Here is my remix on Thingiverse with the unused screw holes filled in for a flat surface.
I also printed out the Extruder knob highlighted in Chuck's video. The first time I printed it, it came out perfectly, but it did not fit. It was too tight. So, I loaded it back up in Cura and scaled it to 105%. It fit perfectly after that.
Unfortunately, my first layer didn't go down so well, so the top of the knob looks terrible. I cleaned up what I could with a heat gun, but it doesn't look as good as I'd like. The rest of the layers printed perfectly, so I decided to install it on my printer.
I decided not to print out the filament guide as I don't think I'll need it.
If you haven't subscribed to Chuck's YouTube channel (Filament Friday), do so. It's a great resource for 3D printing.