well, a CF airbox isn't going to be the best $/hp. But, I don't think you'd neccesarily do one for the HP alone. I think it's really more about the sound. If I had my choice of that list, I'd go for the Evolve box + tune.
I would avoid the cheap airboxes on Ebay. Most are going to be FRP with CF overlays, and who knows how well they are made. The airbox is important to the powerband of the engine, and $1000 is still pretty expensive. a little more gets you known quality.