Hood Scoops have been around for a long time, mainly since the onset of performance oriented cars in the mid to late 50s. Custom hood scoop were usually placed directly above the air intake, with an opening that directed air into your engine bay.
The same theory still applies today. The more air that you can get in through you custom hood scoop and into your motor, the more power it will make. Now, granted a lot of car owners use aftermarket hood scoops are merely a decoration piece, there are some that still use the bolt-on fiberglass hood scoops for the purpose they were first intended for.
Since their onset, there have been changes made to their design and style to accommodate more types of cars. Carbon fiber hood scoops have become popular in recent years because they are extremely light weight and can still be used a functioning body part. Take a look around the store for the right custom fit hoodscoop that matches you vehicle's design and feel.