Benz Sketch

A benz sketch...not my absoulute best but up there.....not the best at shadding.....tell me what u think and how i can improve!!! thanx guys!
http://img352.imageshack.us/img352/8688/benz1yn.jpg

the bodykit seems rushed, and the scoop's are not in proportion (at bottom.)

retry it using a ruler and rectangular shapes to get the proportion right.

Put the ruler in a far away corner. Try it freehand. The perspective you've chosen isn't easy, but it looks already quite fine. Maybe it looks a bit rushed because of the criss cross in the intakes.

sry it took me so long guys ive been really busy...this one is a lil differn't i didn't go so much into the shadding but just trying to get the sizes and shapes right! so a better job but still not perferct......and then i was bored and thought it was kinda cool (the color one)
sketch:
http://img515.imageshack.us/img515/1408/benz4copy3vz.jpg

photoshop:
http://img515.imageshack.us/img515/9836/benz3copy8nh.jpg