I'm not a fitment expert, maybe the people at sto N sho can help, but from the looks of the steeda splitter, it sticks out farther than the factory PP front splitter. If thats the case, this will not work for you. The plate is set up to extend just infront of the factory splitter.
this uses one existing hole to center the bracket on your car, and then two of the screws provided are self tappers that you screw directly into the bottom of the front lip. All said in done, a 5 minute install.