It won't do splits. By hit the button, I mean on the gps unit. There is a single button on the unit, and it's function is to set the start finish.
The unit can't make the dash have any functions that weren't already there. It serves only as a very accurate and reliable method of triggering the stock system instead of the other two options:
1: Similarly expensive and generally flakey IR recievers which need a line of sight, to the beacon, which needs a battery, and gets confused when the sun is just right. Then someone steals the beacon when you forget it at the track.
2: Hitting the starter button on the finish line which is horribly innaccurate.