For example, can I increase the armor rating of tech armor or fortification powers?
Warning: Always backup your character save files and original coalesced.bin file before making changes to the coalescend.bin files...
List item Google and download your favorite coalesced editor for mass effect
Using the editor, navigate to:
biogame.ini > sfxgamecontent > sfxpowercustomaction
All the powers are listed there, and you can edit them to your heart's content. (Just be careful to heed the warning above....)