Two old aerodynamic improvent have already been shown: the NACA-duct in the intake of the air box lead to a slight improvement (average 0.5-1 kph) and the extension of the wind screen shown in my 1st contribution leads to a similar speedup:
Just improving the angle of this addidional screen has a large effect - at some certain point where i never got beyond 33-34 kph i reached 38.5 kph which triggered the stationary speed camera at that point. Meanwhile the canopy has been further closed, but without any additional noticeable aerodynamic improvement.
Back the the aerodynamics of the tail:
the hole(s) in the top of the back plate should have aerodynamic effects, should'nt they?