Here are some clarifications:
In the Auto Root package, you'll find the options to
Option A - root
Option B - unroot
Option C - install BootImg/zImage
A) "Root" works for EG30/EG31/EK02 (ie all the released versions) If you want root for newer versions EL13/EL26/EL29 the Auto Root package works in conjuction with pre-rooted ODIN One-Click packages referenced in the Auto Root thread
B) "Unroot" works for any version (that was rooted with Auto Root or the ODIN One-Clicks). you don't actually need to specify the version, it is the same for all of them. You also don't need a PC to run the scripts. Using a PC is all automated, but if you can't for some reason, just copy the copy2sd\000root folder to your phone and manually run the unroot script. Instructions are in the 2nd post of the Auto Root thread.
C) If you installed a zImage (to get CWM) then it is your responsibility to install the non-CWM "stock" version before you unroot. You also don't need a PC to run these, just have to copy the files to your phone and run the scripts manually. Instructions in the 2nd post.
Aside from the Auto Root package, there are a set of ODIN One-Click tar packages that will get you to stock by flashing (ie overwriting) modem/kernel/ROM (as opposed to uninstalling root, which is what the Auto Root package does).
For the EG30/EK02 ODIN One-Click packages, you just flash them and you are back to stock.
For the EL13/EL26/EL29 ODIN One-Click packages, after you flash them, you will be completely stock except for rooted ROM. Just run Option B (unroot) and you will be at 100% stock.