Rags,
I see your point about spilling water out of my front end.Extending the splitter would increase downforce.Like everything,there is a balance to be reached.Another foot would really mash that thing down.Of course it would look like S..T.Also the further a splitter protrudes,the more pitch sensitive it becomes.That could really upset the apple cart!As for making splitters for our cars,using a flat piece of 0.080 aluminum works,but is really not the best.Ideally the bottom should have a "belly".Just another wing;right?Composites are better suited to this application.Once again;another bolt on part that can be as complex as your time,talent,and budget allow.