I just use the standard filter I get from the local massey dealer. I don't know anything about replacments. There is a guy on here FarmWithJunk I think is his name, he seems quite knowledgable so maybe he can help.
As for 1800 hours - that's not even broken in yet

I'm like you, my Kioti has better hydraulics, brakes, tranny,
4wd and such so I like it for most chores but I keep my massey for brush hog and backhoe use. I'll never part with it.