If the plug wires go directly into the coils with a bit of goop oozing around them, they are non-replaceable. If there are towers and rubber boots they can be replaced easily.
You can get wire splicer thingies - you cut the wires off close to the coils (the wire should be OK there hopefully) and add a length of new cable.
Various models used coils with replaceable wires that would fit on your bike - the CB900 and Gold Wing I think but not 100% sure.
Dyna coils fit with a slight mod to the original mounting posts, and use standard wires and terminals although Dyna sells wire sets that are excellent.
You can get plug caps at most dealers, get the NGK ones from the accessory counter.