Hi Enrico - Yes, I changed the filter. I had used a K&N 204. I replaced it with a HD OEM. I have ordered another filter to have on hand. it's a Hi Flo 175.
I'm refilled with 15w50 full synthetic 3.3 quarts. I used two brands. One is Shell the other is Yamalube.
These oils are expensive. BUT - I get a bit of a discount at the dealership where I used to work part time. Otherwise, I would probably buy, in the US, from Walmart. It's a discount general store. I would get their 15w50 or 20w50.
And I always use a new gasket ring on the drain plug.
When I do an oil change I always clean the low side of the radiator cover. I spray the dirt with a dilution of Simple Green then just water. It's easier to do this when the cover is off. I'm not that lazy, just old!