Saw a picture of this over at the HWC website. Someone found it at Wal Mart.
The finish line piece looks similar to the 4 lane and 6 lane set in that it has track connectors at the end where you can reverse the finish line piece and the finishing gate to point the other way to make it compatible with any 2 lane track setup.
Not sure how to get the starting gate to work away from the set though, since there aren't track connectors on that piece. Might take some modification there if you are into two lane racing.
Or just buy two sets and have the best of both worlds.