I have the Ender3V2 so the Thingaverse mods I printed will work for either machine. These mod are net really necessary but they do make the machine better.
What I downloaded are:
-filament guides (I modded mine to hole a filament run out sensor)
-roller bearing filament holder (needs two bearings, cheap)
-slot covers for the frame struts
-X & Y tensioners covers to keep crap out of them. (if this applies)
-I replaced the MB and Power supplies cheap 40mm fans with 92 mm Noctua fans so I -printed out new cover plates for both off of Thinaverse.
-cable or drag chains to hold all the cables, suppose to make the wiring last long because of reduced strain.
and a bunch of other things
As far as filament goes I generally buy it from our host 3D Printing Canada. Their prices are as good as or even cheaper then Amazon and the filament is good quality, in my experience. From them I have used, Sakata, 3D max Pro, Value brand (problems with one role) with good results. I have used some other brands like Flash forge (always hard to get) and TruePure Premium (made in Canada and very nice) but they are not any better then the ones I have used from 3DPC. Amazon may be cheaper if you have Amazon Prime for shipping but not by much and 3DPC delivers very fast, sometimes less then a day. I have some Euro silk from them but I have not tried it yet. I have only printed with PLA as yet so I can’t give any advice on PETG, I do have a role sitting in the corner staring at me begging to be used. Most people only print PLA but there are times and places it isn’t any good. Outdoors and hot spaces like inside a car in summer. PLA can’t take the heat. Traditionally ABS is is the go to for those but it is a lot harder to print, it has toxic fumes aka it stinks bad and needs mods to your printer. Enter PETG, it can do most of the things ABS can but is easier to print, won’t poison you and you can print it on an Ender3 printer. It is good for outdoors and higher heat loads like in a car. On a side note standard PLA is about the strongest, on average, filemant out there but is brittle, PLA +/Pro is not quite as strong but has some flexibility to it and that can be useful for some prints.
I have only bought nozzles off of Amazon and they where dirt cheap. probably for a reason. One batch looks very nice, well machined interior sides (very important) and the other not so much. Cheap, poor finished interior nozzles can be trouble with filament sticking to them. If you only print PLA then you won’t go through a lot of nozzles so buying good ones (a couple could last years) that cost a bit more is worth it. Again talk to 3DPC about the ones they sell. Buying them, like anything else, off of Amazon is a crap shoot.
As far as the mod to fix the boden tube is that one shown in this video
If it is I can not stress how important it is. It will stop almost all the hotend problems you night have.
If I missed something let me know.