Congratulations on your new printer!

Yes, I had a lot of frustration with the printed parts of the extruder. I remember having to grind down the inside of the hinged idler to be able to seat the bearing without damaging it. The filament hole in the extruder body did not align with the hob in the bolt so we filed down one of the washers that go on the outside of the bearings. Lots of other bits of shaving and filing. There was a ton of cleanup to do on the pieces and some of the screw holes and nut traps had sagged and had to be drilled, shaved or otherwise reamed.

When assembled, the gears were ragged on their surface and very tight even with the stepper at the farthest spot on the extruder. The gears didn't rotate smoothly and the steps of the stepper motor were amplified by the tightness. I was concerned enough to put the stepper on a stepper motor tester to play with it. It ran smoothly so I installed it and it worked perfectly. Now the gears are worn down and mesh better. Unfortunately, the printer has a fine dust of ground plastic all over it from the extruder gears as they "burned in."