Edit: especially when flashing to/from AOKP/CM9/AOSP.
Sent using Tapatalk 2 Beta-5 on AOKP 32 ROM
El26 with cwm is the latest safe kernel to flash with. El29 and later have rogue repacks and are not safe to use to flash from ICS to GB. I have flashed from ics to ics using fd02, fb21, and a few others with no issues(doesn't mean its safe). Only use el26 with official cwm to be safe.