You can use a behavior buff to modify move speed and acceleration. Make it have a short duration and apply it with a trigger or a persistant effect periodically.
You could set the buff up so you can stack it(to move faster) or modify them with catalogs (change the attribute of the buff so the same buff makes units move faster or slower).
You aren't just limited to move speed, you can modify the unit's time rate so it moves, turns, animates, morphs faster or slower too.
Last edited by Adovid : 09-21-2010 at 06:54 AM.