Numerous, Tail and cowl, as needed to compensate for incorrect, incomplete manual, and factory QC problems.
A serious Manual omission - -
Dry fit the vertical tail assembly, and make sure that the control horn will slip between the end of the vertical tail assembly rudder torque rod and the tail wheel mounting bracket. Shorten the torque rod as needed. This is to allow easy assembly and adjustment of the Rudder linkage.
The tail wheel bracket, plywood bracket mounting, and a retained nut on the plywood mount cause binding with the tail wheel linkage clevis and rod.
Grinding with Dremel using a small sandpaper drum and stone seems to be the solution.
The optional interior floor and the tail wheel linkage brass post screw at the servo rub against each other. The screw should be a setscrew, but the size is difficult to find. Grinding down the screw length and removing part of the floor under one passenger seat is a possible solution.
The ESC mounting "box" must be shortened by at least the thickness of the ESC if the fake radial engine is to be used.