Front lip, factory rear diffuser (found on special edition cars) , lower it and put some aftermarket wheels on it. 18's at a minimum in size with 245/45/18 tires.

If you install halo headlights you'll hate yourself because of the light output. Retrofit some projectors in there for looks and great lighting. GPO/GXP spoiler or whatever they are called, they look way better than the standard spoiler.

That's it for my idea's.