Hi,
Thanks for choosing to go with the
MGMAT books! I would agree that it's best to get the latest version of our books, but you might want to consider getting the OG12 as well. Using the conversion documents certainly ins't ideal. We have a pretty in depth analysis of the difference between the OG11 and the OG12 here:
https://www.manhattangmat.com/official-guide-12.cfm which might help you decide.
(Also, just an fyi about buying books second hand: each book comes with a year's worth of access to our online question banks and CAT exams, but once that access has run out you can't renew it.)
Best,
Caitlin Clay
Student Services Associate
Manhattan GMAT