Changes made in my quick sketch:

1) Rear wheel opening moved back, re-arched and widened for 18/20 wheels

2) Front wheel arch stretched back a bit for less round shape 17" front

3) Layed Down rear glass

4) Chop roof to recapture "correct proportion".

5)lose the vent window

6) Tighten and smooth rear bumper

7) look at it and realize that to do it on paper takes ten minutes in real life don't want to consider the hours of hard work.