[PvK]

Er, I believe the cost is 100% of the new components' cost, plus a fraction of the cost of components removed. However, as long as you have enough resources in your reserve, the switch takes place in one turn, and all new components start out damaged.

There is also the 50% increase limit in total resource cost, per retrofit - so you have to have a ship that's at least 2/3 the resource cost of the one you are refitting to, or the refit won't work.

Still, if you have a ship worth at least 2/3 of a very expensive ship like one with stellar manip components on it, and you have enough resources in storage to handle the retrofit, they yes, you can shave (well, lop off) many turns off the time to acquire a very expensive component.

PvK