I have an 03 2500 w/ 6.0L engine and have over 40K miles - many of them heavy towing miles. I would like to check the plugs and possibly replace them but cannot get those metal shields off. I have the service manual on this vehicle but it does not detail this. The manual says to rotate them 1/2 turn before removing them but I cannot grab onto them w/o deforming them and do not wish to replace the wires if I don't need to. Is there a special tool for grabbing these things??

There are tools made to remove the metal shields.
Usually a quick twist will release the plug wires from the plug