I use the ultimaker robot as a test for all materials, I used to have a problem with the left ear side but that's now better as ive changed the fan housing, now the left ear is fine just a little prob on the right ear.
There may be some nuts and screws that need tightening, as well as making sure you have upgraded the firmware. I would recommend building and changing over to Roberts feeder.
For PLA and XT I tend to use hairspray for the bed adhesion, I print almost everything at 0.1 or occasionally 0.06mm layers and with a speed of 50mm/s, PLA at about 210 degrees C, using either Faberdashery or ColorFabb filaments.
Do you have a picture of what your slooks like, as im not sure if im just expecting too much tbh. I saw the different fan mounts but what is the benefit? also I was a bit scared about unscrewing stuff!
I litrally haven't messed with any settings at all, do I do that in Cura or should I be doing that manually when the print is going?