Hi everyone! I'm a brand new member here - I saw this and cooked something up:
Basically, chop part of the rear cargo area out, bend down the roof sheet metal and smooth it down; install wheel pants over the rear wheels; smooth out all the gaps between the body and bumper covers with fiberglass; fill in the lower front bumper "intake". Also, smooth out the gaps between the headlight and bumper cover with fiberglass.
Also, replace the sideview mirrors with back-up cameras; install "Mooneye's" hub caps; extend the leading and trailing edges of the front wheel wells and flare out the leading edge; also, a set of lowering springs and shocks may very well be in order.
Also, install LRR (Low Rolling Resistance) tires.
EDIT: Also, add a windshield wiper cowl to retain the wipers and make the car more aerodynamic.