Like everyone else said above, ram air is pretty much ineffective. But it might be considered a source of cold air. If directed over your air filter as mine is (California Dreamin Hood) I might be getting a small cold air benefit. But might and small are the key words. I bought the hood for looks and it was an expensive undertaking. Hood and paint cost about $1,500. Staying with your stock aluminum hood and going with a stick on hood scoop would be a hell of a lot cheaper and still have a nice cosmetic effect.
One other thing about fiberglass hoods. It is unlikely you will be able to use hood struts with them. I had hood struts on my stock hood with no issue. When I replaced it with my fiberglass hood the struts bowed the hood when closed. I was afraid of cracking the hood so I took them off. A friend of mine had the same issue with a Steeds cowl induction hood. I've seen this on several other fiberglass hoods as well. Maybe someone makes a strut that will work well with fiberglasshoods. But the majority of them out there do not.
You may also need to consider hood pins if you change your hood. It will depend on how fast you go. But in general the fiberglass hoods float more than stock hoods. This can make you rather nervous and opt for the hood pins. I don't like the looks of them so I just keep my car underr 100...most of the time. :hihi:
06 GT Premium, Windveil Blue, Auto, IUP
Mods: Midwest Auto Gear Engine Plenum Cover, Sequential Taillights, Demolet Tunable CAI & SCT Tune, CDC Quarter Window Louvers, Billett Aluminum Interior Items, 8" Shorty Antenna, Powder Coated Valve Covers, Braided Hoses, Flowmaster AT, California Dreamin' Hood, CDC Classic Chin Spoiler, Honeycomb Rear Decklid Blackout Panel, 35% Window Tints, SHR Lower Grill Inserts