It looks a little weird but it beats making another expensive splitter!
To help reduce spillover we did this little end plate extension for the bottom of our splitter out of some leftover scrap carbon and the channel aluminum left over from the air deflectors.
Here are our completed end plates in place on the car.
When looking at Verus Engineerings CFD you can see how the endplate really extends the stagnation hot spot on the front of the car. This is all going to increase downforce. You can also see how the endplates extend the low-pressure zone under the splitter all the way to the sides of it. No leaking out to the sides. You can also see how the hotspot at the front of the tire is really reduced. These parts probably increase the effectiveness of the splitter by 20% without much drag penalty. They also reduce wheel well pressure-induced lift which will also help front lift.