It's incredibly easy to mod. All you need is ~$30 to buy a flashcart and you can mod/homebrew/hack away. There are other methods, but they're more difficult to carry out. Just a note that I'm not providing any links to hacking methods or advocating for homebrewing or modding your 3DS.
In terms of mods I'm applying, I'll be applying 2:
- The Good Guy Garon mod, which overhauls the story of Conquest to make it actually good, and
- The Same-Sex Marriage Patch, which expands support options as a whole, predominately adding same sex supports for both male and female characters
For Birthright to make it interesting I'm thinking of doing a PMU (Pick My Units). What would you guys think of that?