Thats gonna be a sweet Swinger... Me personally, I wouldnt put the wing on that car.. However, it doesnt matter what I think.. lol.. If you like the wing, go for it dude.. life is short..
Also, when you get closer to the point of adding the wing (when the cars all ready and in paint) mock a go-wing up with some styrofoam and cardboard... place it on the car, and just leave it there a day or two.. walk around the car.. See what you think, before you commit to drilling holes.. Just a thought