The grey ones are no problem (they pop right open), I just don't want to break the green onesYou literally have to crack open the old fan shrouds, remove the fans, then pry open the new "Green"(at least they were to me) fan shrouds, remove said fans, and put new fans in old fans shrouds.
The wiring is the same, you need to be careful in removing the old fans to not damage anything too terribly much.
EDIT: yeah, just figured that out - the green one needs much more force. Thanks for the help, now I just need to cut the grey shroud to fit the new fan