Upgrade / Unit repair

I've never known an aircraft carrier to be given a speed boost, increase in armor and a larger flight deck while at sea . While research is used to upgrade units, those units should be routed to the factory that builds them for the upgrades to take place. This could also be the same for unit repair.

Suggesting a unit price to build new and the unit goes in for repairs with 20% health, the unit should be allowed to be repaired to 100% strength for 80% cost and build time. However, when it comes to infantry, we aren't talking about machines. We are taking about soldiers, who need to attend hospitals (urban) or field hospitals (non-urban) for repair. The Barracks could be for upgrades only, such as issuing better weapons, giving more advanced training, etc.

Also, as a quick note on research ... Could we possibly have research buildings put into the Province Economy list so the ability to research isn't added as a freebie and must somehow be purchased? Perhaps research buildings generate a given number of research points that affect the research times.