Easy Appearance & Performance Accent -
There are many paths to choose from when it comes time to changing the appearance of a car with performance in mind. Some consider modifying their car in a way to broadcast their performance intentions to the world and possibly even outer space. Wings extending three feet off the trunk, racks of lights, and more body kit than there is actual car underneath is apparently the way to go for space alien performance. Others value subtlety and actual performance gains—even if small. Sometimes the most effective path to take is a simple blend of subtlety and effectiveness.
Aerodynamics in custom car modification is an area where it's easy to do more harm then good. Pushing a car through the air requires a great deal of energy. Any obstacle in the way of airflow creates drag. So that three foot tall wing may look sporty, but in reality likely slows the car down. Smaller aerodynamic devices can add a bit of style without causing more harm than good. While genuine performance gains are difficult to measure without something like a car-size wind tunnel, even a minute change in airflow over a car or wing can make a dramatic difference in performance.
The Gurney Flap
An aerodynamic case in point was a length of aluminum that became known as the Gurney Flap. The story of the flap's creation follows a challenge by driver Bobby Unser to his then boss Dan Gurney to come up with something to make their 1971 USAC racecar turn faster lap times. Gurney suggested riveting a short right-angle flap lengthwise along the top trailing edge of the car's rear wing. The increase of rear downforce on the racecar was so dramatic that the team had to add downforce to the front of the car. More traction with a minimum increase in drag was the result. The Gurney Flap became the team's secret weapon to win races and was later proven to be effective in a McDonnell Douglas wind tunnel.
Riveting an inch or so tall piece of right-angle aluminum onto a car might do the same job, but the holes left pop rivets drilled into the trunk deck will not seem like such a great idea when it comes time to sell the car. Fortunately installing aerodynamic bits in less than an hour is as easy as opening up a browser and firing up eBay Motors, or similar. In this case the spoiler came with adhesive strips already in place, and was even paint-matched ahead of time for a seamless and factory looking install. While winning races and making history may not be the end result of an hour in the driveway, a spoiler can certainly add a sharp performance accent with minimum impact.