There's a really weak explanation about enthusiasm in Help, so, I'm wondering.. first off, it has 15 levels, so I'm wondering, what's the effect of those lvls? Do they improve your performance by %?
Yes, but I'm not sure exactly how much that percentage is. For example, the general consensus is that a team that uses TIE with an ENTH level of 8, would do just as well as an equally skilled team that used Normal and had an ENTH level of 5.
How would it play out between equal teams having, neutral arena, one having 15 enthusiasm and playing it easy vs a team with 10 enthusiasm and playing it normal?
The team with 15 enthusiasm should win, assuming there are no injuries/foulouts, etc. Out of 10 games, I would say that the team with 15 enthusiasm wins at least 7 times. However, this is just my opinion.
Teams that have higher enthusiasm play better than if they had lower enthusiasm. Compare it to real life. If a team isn't enthusiastic about playing, they will probably play worse than usual. On the flip side, if a team is pumped up to play, they will probably play a little better. Hope this helps.