Hi!

I'm preparing for the GMAT using the official review guide 12th edition. I found the review part quite useful and I'm now moving on to get a good number of questions for each of the 5 types done each day.

I'm currently planning to finish the 800 questions of the book in 9 days, making notes of those I fail to revise them later. I have two installers of the preparation/simulation computer test from the www.mba.com website. Each of them should have two test although I'm not sure the two installers are different.

Is this going to be enough as a preparation?

At the moment (using the book's questions) I'm around 80% in problem solving, 90% in data sufficiency and over 95% with the verbal stuff. I'm also very quick, whenever I had a run of questions usually between 15 and 30 I timed myself and the time I used was anything between half and 80% at the most.
Given this and the fact that I'm aiming at 700, will I be ok? I tend to do well at exams and, call me crazy, I'm earnestly enjoying preparing the GMAT.

At the moment, the only risk I feel is that the questions in the book may not really be as difficult as those of the test? Or rather, I think it'd be very useful to know the "difficulty" of the questions. E.g., being told that this question is in the 700+ range, this other is in the 600s and such.

Shall I use other books and/or test simulations?

Also, what are the best centres administering the GMAT in London?

Thanks for your help!