A few modding tricks:
If you have a lot of components, some of them might be obselete at high tech levels, and unlike SE4 it doesn't seem like you can get rid of them.
But this isn't correct.
All components take formulas for their requirements, and those accept "less than" as an option. So you can make a component that disappears once some research level is reached, and a better replacement becomes available.
Say you want the Cannon to appear from levels 1-5 in Projectile Weapons, where its replaced by the DUC. You'd put this in the requirement field:
(Get_Empire_Tech_Level("Projectile Weapons") >= 1) AND (Get_Empire_Tech_Level("Projectile Weapons") <= 5)
the (s are important- they let SEV know where a funtion like Get_Empire_Tech_Level ends.