haha, you guys think everything is done with filters now days..
its not, anime cars like this are all done by manual in photoshop, thats how i did mine..
see pictures below
this one is not finished yet
Its a very long process of outlining, and cell shading (basically uses a method of selection and filling in the area you want with the color you want)
Its pretty easy once you get the hang of it, but takes awhile.