Check the blind nuts on the wings where the wing attachment bolts go..both are weakly glued...Also the flyer at our field
checked the incidence and found 1 wing off..and the anti-rotation pins fairly weak..something you might consider upgrading in strength. The top of the cowling tends to bend and eventually will show minute cracks..on top..i think because the thickness of the cowling is thinner in that area..maybe some fiberglass reinforcement may help cracks from appearing over time.
The plane is a fantastic arf..with great colors and build...and with the YS has plenty of reserve power..you will love this plane.

bobzilla
p.s. I hate the UCD..i can name gobs of thing wrong with that arf..but, please don't get me started!