Just to clarify...
There is a difference between a wing and a spoiler.
The purpose of a wing is to create down-force for traction benefits at the rear wheels.
The purpose of a spoiler is to create a bit of turbulence in the air-flow behind the car "spoiling" the air so that it doesn't create a vacuum pocket or low pressure wave behind the car, which helps the car go faster with less effort.
For the most part, a wing on a FWD car is for looks alone, but there's bound to be at least a little bit of benefit from it (although, probably not enough to really notice).