Re: Plug wires..
I've tried it on the older Force Presolite ignition system coil. The core inside of the spark plug wire is solid stranded stainless steel and is spot welded to the winding in the coil. You can't solder a replacement wire to it as the solder will not stick to the stainless steel. I've played around with it and I don't see how you can replace the plug plug wire. You have to practically destroy the coil to do it.
The 1996 and later Mercury style Thunder Bolt CDM ignition systems, the spark plug wires do indeed "unscrew" from the coil. And yes, they also have a solid stranded stainless steel core, not RFI suppression type like used in most automotive applications. Very easy to replace the plug wires on these.