yes they are similar. Terror is to fill with great fear and Shock and awe is a violent attack that cause fear.
The liguistic difference is one of degree. Terror is a Great fear and awe is a lesser degree of fear. yes, both a Terror attack and Shock and Awe is meant to instill fear, however, you have to take into account how it was used. In the case of Shock and awe, the U.S. warned Iraq for weeks and then gave a specific deadline whereas terror attacks are generally conducted with warnings.
And I agree the difference between the two are smaller than most war supporters would like to agree too but I would also like to say the difference is significant enough to note in this answer to you query.
I would go on and say that September 11th was done without warning but I'm not convinced of any real connection between Iraq and al-qaeda so I think the comparison would be unfair at the moment.