Let's organize a tournament.

In my opinion, if the goal of the tournament is simply to hold it, then you can use the original version. However, if the aim is to attract new players to the TE mod, then it should be played on that mod. Participating in the tournament might motivate many people to learn more about the mod. You could create a thread where newcomers can ask questions about the mod; fortunately, there are people who can answer them.