I have a 2003 BA GT and it has just dropped a cylinder or something. It just started running rough like its missing or cutting some cyliners back. I am thinking about changing the spark plugs. These are a four valve head and I have heard a lot about the 3 valve heads breaking plugs when removing them. can anyone tell me if the four valve have the same issue or did they fix it with these. It has 110,000 on it and never had plugs removed.

4V doesn't have the same issue as 3V with plugs.
You may find you have a dodgy coil rather than the plug itself which of course is an easy fix and your best bet is to buy a full set of Motorcraft coils from the U.S.