MSD coils by themselves don't REQUIRE a wire change, but there is a little to be gained if you do so. Plugs make no difference in wire selection.
The MSD 8224 coil was designed specifically to work with the MSD DIS-4 ignition system, which produces a hotter spark.
The coil ratio of the MSD coils IS slightly different from stock coils, but not enough to make a huge difference. You're still initiated the sequence with the same voltage from your ICM as before, and the different turn ratio of the MSD coil is gaining about 5% or so hotter spark. That'* a guess, btw. I haven't measured my MSD'* in ages. It HELPS a little bit to have a good-quality wire to gain the most out of that, but it'* not required.
The main advantage to going with MSD coils is that they're about the same price as stock replacments, are a LITTLE hotter if you're going to take advantage of that, and they look cool