"One problem of Chaos is that it adds the morphed unit's current armor, damage, health and mana bonus received from items, auras and srength, agility, intelligence to the stats of the resulting unit. That means it's not a very good idea to morph heroes using chaos until Blizzard fixes those bugs. Ordinary units can't be affected by items and hero stats, so the only problem are buffs received from auras. Those buffs can easily be removed before the conversion and are automatically added again afterwards so that's not a real issue."
Now that's the source from:
http://www.wc3c.net/showthread.php?t=81742
Take a gander, great info right there

Hope this has helped you.