Hi Mowerfreak,
In relation to the ignition units that contain the module and coil as a single unit, rather than the earlier two piece setup, I was wondering exactly the same thing.
Could I pull the plastic covering off and affix a new module to the wiring of the coil?
It would be theoretically possible, but depending on how it’s been constructed will determine the feasibility in a practical sense.
As you say, the change was most likely economic in nature. I much prefer the setup with the coil and module wired separately. So much easier to deal with.