I dont want to pull the newb card on yah, but next time you do something like that just put it in the Photoshop Lounge.... Thats where photoshopped pictures go.... With that out of the way.....
If you wanted to motion blur the windows what you could do is make a copy of the places in the window you can see the Background, make those copies into a new layer..... Motion blur that layer and make that motion blur semi-transparent.... That way you get the effect of motion blur, but it doesnt mess up the car.....
Otherwise, nice design....