I haven't since I got Starcore. You don't get enough repair time to win with anything but a popup in Starcore, and even that's hard. In order to make a bot that can win tourneys, it can't have very many parts on it.
Which means it IS possible to win in DSL with the right design, and I still do tourneys in DSL (though admittedly not very often).
So... yes, sorta.
And it is possible to make AI race, just check the DSL 3.0 preview thread.