No no no, you dont cut off the connectors! Why would you do such a thing?!
There is a special tool (costs about 6 or 7 bucks) that is specially designed to remove the molex connectors. I had a buddy who did it the way Dav536 did it, but it took him the better part of an entire day to do it, and he recommended that if I do it I get the tool.
You can also get different colored molex connectors, and a new atx connector, and every other connector.