I wouldn't make the lines so hard. I would use dark grey for the windows and then maybe use a (large) cloud filter of to the right side in a lighter grey. That way you don't have such straight lines. Oh, and I'd remove the one from the side window. It draws the eye through the image and gives a false 2D feel to it.
________________ Why settle for great when you can have HOLY SHIT?!
Check out my daily driver. It's a Stillen built 9,325 watt 300ZX.