Use this tutorial instead:
http://www.staredit.net/index.php?tutorial=103Player 14 is more detailed than that "2x & 4x Map Speed" tutorial crap.
If you place a map revealer it only speeds up the animation. Placing an interceptor does the 2x map speed and some units will not attack. Placing a scarab does the 4x map speed and most units will not attack.