its pretty kool
but i have to agree with u, the blue corvette dnt fit too well :P
with the second pic, on the right hand side it looks like the car is on floor with the flag flying behind it, but on the left, there is no floor......
IMO, i think it may look better if there was 'floor' on the left sid aswell ;) - or just enough to make it look like the car isnt on the flag :P
still.....
its looks DAYUM sweet for a first sig
keep it up dude

EDIT:
anutha thing u may want to think of is adding a few adjustment layers (click layer>adjustment layer) to change the colour of the yellow car slightly so it looks a lil more burnt (like the BG)