From an artist's viewpoint, here's the opinion. The one of the two cars at LeMans is a little too much like Tim Layzell.Watch out he might punch you in the nose!
http://www.timlayzell.com/motor_art_originals.htm
and the Lemans track is at last 3 times wider--I know, I've been there. Still I like the strong representation of solid colors ,it's the kind of painting that looks good in a very big living room from a distance. The pencil drawings of the Cobra Daytona show very good control of the pencil and good restraint in not overdoing any aspect. The black and white of the GT40 side view has a background competing with the car too much. The rear 3/4 of the Mk. II is a nice detail piece, again showing mastery of the medium. You should try printing the pencil works on watercolor paper, say 80-lb. weight. I can connect you with a printer if you don't have one. One trouble with places like Fedex is that they won't allow any paper but your own. You have to find a printer that will let you supply your own paper, the thicker the better. Good luck,you have a lot of talent, just have to find your own style and develop it.