The classes provide a lot more than just the books - if they didn't, nobody would take the classes. They'd just study from the books! My students don't even bring their books to class - all of the bookwork is done as homework.
Whether you need the additional instruction depends upon (a) how much of a score improvement you want, (b) how good you are at standardized tests already, and (c) how motivated and disciplined you are to work on your own rather than following the structured syllabus of the classes.
FYI - our program is a LOT of work. The classes run 9 weeks and most people need 2-3 weeks of review after that before taking the test. It will be challenging to do all of the work in 4 weeks. (Not to say that you can't or shouldn't do it - but be aware what you're getting yourself into! My students do 10-20 hours of homework a week outside of class.)
Also, if your timeframe changes, we do offer live on-line classes - they meet for the same amount of time and use the same curriculum as the live in-person classes, and you are meeting with live instructors at a steady time once a week - you just don't actually meet face to face. All you need is a broadband connection; I have students from all over the world in my classes.
Good luck!
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Stacey Koprince
GMAT Instructor
Director of Online Community
Manhattan GMAT
Contributor to Beat The GMAT!
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