I'm going out on a limb here, and everybody should feel to insult my taste, but I think it looked a little better with the wing on there. Here's why:
As far as swoopy ricer wings go, that one doesn't actually look half bad. It also balances out the car a little bit. The enormous cowl hood and the chin spoiler add visual weight to the front of the car. The side skirts do the same thing for the sides, and the wing did the same thing for the rear. Without the wing, the car looks a little nose heavy.
If you insist on a cowl hood, and it sounds like you do, I think it would look better if the bulge was about half the height of the current one. Another thing that might be cool would be to "invert" the stock hood. Stock, it dips down just a bit in the center. I'm not talking about the peak in the center, but that the middle half is about 1/4" - 1/2" (?) lower than the ouside half. How about keeping the same curves and lines, but raising this about that same distance above fender level instead of below? Either one of those things would reduce the visual weight of the front.
Then find a similar height cowl to graft onto the decklid to add some visual weight to make up for the missing spoiler. I've seen one off of a Mustang or something that looks good and blends in nicely.
I'm not a big fan of the chin spoiler, either. Have you seen
the one that Michael Smith did? I've seen it in person and it looks good. I think the best looking thing somebody could do would be to take his design, but extend the solid part of the nose down a bit so the hole isn't quite as big.
Then, a little smaller side skirts to even everything out. I don't think the current ones blend too well at the front edge of the door, but I can't think of any easy way to fix that.
So basically, the same design that you have, but toned down just a(nother) notch.
That S2000 silver is a great color. It'll look great with your wheels.
I think the fastback GT has incredibly clean, nice lines right out of the factory, and it's actually pretty tough to improve on. The things that work the best, in my opinion, are things that blend in to the existing lines, instead of just adding more. Glad to hear you're getting rid of the stick-on scoops on the nose.
So that's my opinion. Feel free to use or disregard anything I said, and no offense intended to anybody that disagrees. And at the end of the day, hey, it's your car. Do what makes you happy.