The '!' sign on units for quests.

How can I make unit have floating '!' over it like when it gives you quest? :(

Its a special effect action.

Special Effect- Create special effect on unit with path <leave this on default>

Wich special effect is it?

Its the default one that is in the box when you select the action "Special Effect - Creat Special Effect". Just select it, tell it what unit to creat it on and your done.

\TalkToMe.mdl is the one.

I personally find creating a new ability based off Sphere, removing projectile graphic and changing art attachments to 1 and graphic set to that SFX, and adding/removing that ability as necessary from units via triggers to be much easier than fiddling with special effects, which are a pain to keep track of if you have a lot of them going at once (unless you happen to enjoy memory leaks).