To the Revell stuff now: it have some points that could be improoved: weel arches and general smooth appeal:
Revell stuff, front weel arch:

.. and the pininfarina designed stuff, the real one
Like you'll see the revell arch's edge is very wide, almost 3 or 4 times more; also the shape of the arch is more smooth, rounded. The same in the rear one:
Ok I guess image better than 1000 words with my crappy english:
handy mill down fenders
finished with wet sandpaper
start to look better to me