Hi kk12,
The main OG is a great book for practice questions (and most Test Takers use some version of that book during their studies). The subject-specific books can also be useful if you're looking for additional practice question in either the Quant or Verbal. However, any combination of those 3 books will likely NOT be enough study material for you to achieve your goals. They are great sources for practice questions, but they're not designed to teach you the Tactics, patterns or little 'secrets' to the GMAT. As such, you'll likely need a wider array of practice materials.
1) What is your goal score?
2) When are you planning to take the GMAT?
3) Have you done any studying for the GMAT so far?
GMAT assassins aren't born, they're made,
Rich