That's pretty much how I'm planning to study for it... 2 months, using Manhattan.  Dreading it... was never a math guy, and my reading comprehension is horrible.

GMAT prep is a little different from CPA exam prep. GMAT tests basic knowledge and skills. In terms of basics you are what you are: in short term you can't improve basics much. Hence, the goals of GMAT prep are only better time-management and learning how to make educated guesses – skills necessary for any test. Whereas in CPA exam prep you can improve by gaining tons of specific knowledge.

I am really a math person. Verbal section was what caused me a major problem: first, I am a slow reader, second I am a foreigner. My first score was 610. Three years later I scored 680, which I attribute to improving my English skills. Two month later I scored 660, confirming you can’t improve in a short term. It took about 2-3 months to prepare for the tests