The front spoilers mentioned are pretty much all you can do about "front" downforce...although they really don't make too much of a difference unless you're on a track.

Addressing the rear wing issue:

While rear downforce sounds dumb and takes away traction from the front wheels in the event of a drag launch, a rear wing does promote high speed stability. Mugen makes an excellent adjustable rear wing, although it is pretty huge and will most likely draw glares from the hardco jdm anti-riceboy crowd. Unless you're making some serious power and track like a mofo, I don't think a rear wing is really necessary.

But the front aero pieces will do you some good and look pretty slick IMO

Shingo