Now, if someone would reintroduce the F-20 without the fake air intakes, or, if the fuselage space is needed, fair in the intakes. That would eliminate a lot of drag.

I would rather they provide the retract pockets and let me install the landing gear of my choice - such as Robart's.

Shortening the nose a good bit would be a great idea. Less tailweight would be needed. Lower the canopy a good deal - still less drag.