I know this is a tough question without a wind tunnel, but obviously I dont have access to one. So heres what Im pondering, I have a asphalt modifed I race locally and its a IMCA class, which basically means the rules are made for dirt cars and we are the only track that races them on asphalt. Long story short, I can run a windshield on my car but no one has tried it "that I know of" because you wouldnt run them on dirt. Heres some pics of it, I want as much downforce as possible, but with a windshield in place would it create turbulent wind off the back of the roof and render the rear spoiler useless?? Im not too concerned about drag, more down force is what I want. Whats your thoughts, windshield or not? and why, how about a rear window?