Do I get the bonus from Enthusiasm every game or only when I use Crunch?
Your team performs better the higher the enthusiasm is. Crunch/TIE/Normal is sort of a multiplier for the specific game; your team performs some percentage better than normal for their enthusiasm with a crunch and somewhat worse with a TIE. But a TIE with 9 enthusiasm is almost certainly better than a Normal with 5 or a CT with 4, for example. Other people I think know the percentages better and can give more precise estimates, but I find that it's generally the right decision to TIE everything unless you absolutely need to normal a game, and CT only in very specific circumstances.