740 (49Q, 41V, 6.0 AWA) by an architecture major in 17 days

If you already have adequate study guides, then, if i were you, I would splurge for the manhattan tests. More than anything, they are useful for identifying problematic areas. They will give you a good idea of how you are going to score on the real test and help you adjust to the clock. I used the tests to hone in on concepts that I didn't understand completely.
If you are planning on studying from the tests in the way that I did, it takes a ton of time...I spent several hours each night, either taking a test or tediously going over the missed problems and concepts. Maybe not the most efficient use of time if you already know what sections you need to study most. I had not taken a math or English class since high school, so I really needed to spend the time understanding concepts.

Congrats!!! That's amazing that you were able to get such nice score in so little time.