Of course, we have an opinion. And it should be noted that from an aerodynamics standpoint this topic can get very technical and deep. We won't bore you with all that scientific mumbo jumbo. For us, the idea of a wing is 80% looks and 20% effectiveness.
Whether you are a GT Style Wing fan or "Duck Tail" style fan both can have a positive effect on the overall look and performance of your car.
Obviously, most track cars or cars styled as track cars typically utilize a composite element GT Wing like the one pictured below for their ability to create larger amounts of downforce on the rear of the car.
The popular Duck Tail Style or "Rocket Bunny" Style wings are very fitting for street prepared cars (pictured below). They are typically pretty low slung and nicely stylized to flow with the lines of the vehicle. We are BIG fans of these types of wings as we feel they add to the over all aesthetics of the car.
So, depending on your personal vehicle style either of these wings could suit your needs and desires to build an eye catching project car. Whichever you choose, make sure to measure twice and drill once. No one likes a leaky trunk. ;-)