It will do more harm than good.
1. If the car is at stock ride height then the splitter will angle up. That will cause more up force than downforce, so you will actually be less stable at speed (even highway speed it will hurt stability)
2. Your bumper isn't flat, that huge gap between the 2 pieces on the sides of the bumper, air will go straight through that.
Take a look at Brett's Roush. How he used ABS plastic to make a splitter apron so it's entirely flat and pointing straight instead of up.
Bullitts are better than Bullets