Quote Originally Posted by Shinji Ikari
I just finished the anime and was wondering where I should start my reading. Do I have to start from vol 1 because the anime is way different or can I just jump into the middle of it and get a good feel?
I would advise reading it from the start. If you didn't manage to get the uncensored dvd rips of the first half of the series, you will have to start from the beginning. Otherwise, you could probably start around volume 8. It will overlap with the Shrine episodes (you should know which ones I'm referring to, they are midway in season 2 of the anime, which were episodes 14-26) and from there, the series diverges.

EDIT:
The anime specifically diverges at volume 8, chapters 89-90.