Hello Shapeshifters
No this mod doesnt replace any items. The new items are balanced so it doesnt gets in the way of normal item.
You can freely decide to use the old rocket launcher if you need more damage or use the new rocket launcher if you want more range.
Additional information:
For terms of defense:
If you want to properly defend your base you need to place a few of the rocket turrets down and give it some few turrets as back up so that the enemies might run into a deadzone.
Sadly there is currently a targeting bug in the mod (wich i am not able to solve because of my bad Lua skills) wich needs you to make sure that there are not too many turrets in one area or the turrets will shoot at the same enemy multiple times.
This is why i recommend you to build vanilla turrets. Anyway nothing in this mod is meant to replace the vanilla items but are rather an addition so this is why i said to make sure you have normal turrets next to the new turrets because they are just meant to minimise losses and not to totally get rid of them.
Anyways: Have fun with the mod. LG samy115