While I've only tried on two coils so far, I personally I don't think it is possible to remove the retaining clips and wires from a relatively used coil without them breaking. The locking tabs are only half the problem, there is also silicone(or some type of adhesive sealant) down in there and that seems to hold them even after you break or have the tabs pried out.
Once you get them out, broken retainers or not, you have to clean all the goo down around the center electrode prong and then mash, twist, push the new wires till they make contact and go in. I got a set of the Taylor wires and while they are very nice, without some reasonable retaining system I couldn't see them staying put or keeping connectivity. I pushed, twisted, jammed, siliconed - gave up. I could get them to make connectivity but just a wiggle and the ohm meter wouldn't read anything.
I bought the Nology and while I have no run time on it yet, you just crimped GM HEI style terminals on one end of the wires and click snap you're done. Much nicer so far.