Although I myself admire simple Mehrans, but I have tried to give my tips on improving the Modifications :-
- The Back and Side skirts

(i) Cut the body to get a curve, avoid straightness.
(ii) Paint the Lower part black.

(iii) Paint the Side skirts black as well.
- Front and Side

(i) Cut the body to get smooth curve, avoid straightness.
(ii) Paint the lower part black
(iii) Get the Bumper a balanced look. It seems to be improperly made.

The Backlights are good, but I suggest to replace the Indicator bulb with such a color that your Red sticker converts it to Yellow/orange. You might know that Orange/yellow color is easily detectable for the human eye, and is not just a Convention to keep indicators yellow/orange.
For the front, get the Indicators joined in the Headlights. They might not look good on the Bumper.
Do not trust mechanics much. They might not be concerned and might not tell you if something is wrong.
I think you should not remove the body for the time. Keep it for some time. Maintain it and keep it cleaned.