Here is a link from "The Don" on RCGroups who sells and balances EDF's for several different sizes of jet type models.
http://www.rcgroups.com/forums/showthread.php?t=1673281
This guy has operated Dons RC in Ohio for many years. I ordered items from him years back but have noticed lately that he is somewhat reluctant to ship outside the US.
Anyway he has a wealth of knowledge for us to ponder over, so you might get help here if your upgrading a project from stock.
Bill