Is it possible to transfer powerplay weapons, with engineering effects, to another ship using the buy back option?
I know it's possible with normal weapons but I wanted to know if the effects transfer as well.
Sell the weapon or internal to a station. Switch ships. Buyback weapons from station. Complete.
Be aware that the items only stay in the station for 10 minutes, so don't take too long.
Module storage was added in 2.2 Guardians. Use it to transfer powerplay weapons or any module with engineer's effect.
Also you can buy several powerplay weapons to apply effects of different engineers to them. Then you can store them in the module storage to a choice between them when needed (e.g. when you decide to buy a small ship as PowerPlay weapons have small size).