Yes the tailwheel is one that most people do, but forget to mention because it doesn't stand out. If you use the stock set up a few bumpy landings will have the rudder damaged, even if it is not visible damage. All of the bounce and stress that the tailwheel is subjected to goes straight to the hinges and will eventually cause them to fail. Another one I recommend is adding a doubler from the aft-wing former to the next one behind it (F-3 to F-4 I believe). This is a stressed area and I have heard of the fuse failing when doublers are not used.