I was looking into purchasing a wind deflector for my 2007 335i cabriolet but i'm hearing some mixed reviews. Anyone know if they're worth it? Do they actually keep the back seat cleaner and reduce wind noise for the driver? Or is it just a pretty add-on for people with too much money (which I am not) . IF your unsure about the part i'm referring too, it's the black removable folding piece that attaches to either side of the rear side wall of the back seat area. Any info would be appreciated as the part costs around $775 taxes in from the dealer.