Dude, reconsider your title man! I wish I could draw like you, one thing I noticed though is some of your cars tires are sunk into the side of the car. How's it suppose to move if the tires don't touch the ground? Try dropping some of the tires and adding some buffer room. Even low riders have more space than that between them and the ground.
I think the problem with pen&ink is that there is no Ctrl+z command.
writers and artists have a lot in common -- we both draw from life, we both paint pictures, and we'll both spend to many sleepless nights on our work.