If the Cw value is 0.29 then there is still lot of things you can improve even when that is very small car. Biggest gains will come from engine ventilation and cooling ducting. + all the basic aero mods.
For the weight 50 kg is not so much in my opinion. You can lose just 20 kg by installing a smaller fuel tank
. Bumbers are plastic. Hood is aluminium. You can remove the rear seats etc etc. Put plexi glasses which will actually be legal was it 2012 in eu?