I don't know where you guys race, but at the track you can't have your windows down or your sunroof open. They won't let you run. On the street it's a different story.
Generally, you don't race for 1/4 mile on the street. You race until the person in front shuts down. In this situation, drag isn't really a factor. It's after 50 mph or so when you really shouldn't have anything open.
I always have my windows down when I'm at the strip and stuff. How else am I supposed to hear the ricers talkin' sh!t and the girls asking me to pull over?

After the first v8 guy comes and invites me to some real races, though, my windows stay up.