Probably doesn't need its own pref sections. Why not just add a checkbox in the default e-tard options to reverse the effects? It would be cleaner and less menu clutter
1) i dont think any pref system allows you to modify the general pref gui window, plus i have no gui editing experience
2) having them separate allows you to run both etard and reverse etard together
example:
etard: desu
reverse etard: nya
>> all messages must have "nya" but cant have "desu" in them