Lowered sports suspension?
What alloy wheels do do have? (if you have the 17" sporting ones personally I like them and think they add an edge to the car)
Exhaust system?
Front splitter?
De-badged grill?
pick a colour scheme which suits the colour of you car and mix the colours... i.e. if your car was white you could powder coat your wheels black and get black mirror covers.
But on the flip side I would consider thinking outside the box, the best modification you can give to any car is a good set of tyres and stiffer, sportier suspension in my opinion.