[Fyron]

You would need to alter their research files to be able to research the higher levels. Also, you might need to fiddle with their ship designs, depending on the nature of the changes to weaponry. Changing the size of weapons definitely requires changes to ship designs. But just adding more levels with more damage and such only requries increasing the level they will research (before completely reaching the end of the Research file, thus starting to research all unresearched techs, possibly just in the order they appear in the TechAreas.txt file).