I am thinking of getting a Lexan road bike fairing. I have a brochure from ZZIPP Designs in California. They are pretty pricey --$190 plus shipping. Has anyone used one? Do they improve your speed in any significant way? Zzip advertises: "high clarity, easy on and off, help in headwinds, light weight, withstands crashes, adjustable mounts, go faster." Waddayathink?