Eliminates additional cost to prototype new units at this base
The unique thing about the Skunkworks is that while it's definately a nice thing to have, you don't need one in every base. Most facilities either help thier specific base, or help the whole faction cumulativel. With the Skunkworks, you onll need enough to meet your prototyping needs. Build a Skunkworks in one or two well defended, high production bases and let those bases handle all the prototyping for your faction, ( A second base is a good idea, in case one base becomes involved in a secret project or expensive facility when you need a prototype, in addition to simple guarding against mischance.) Other than civic pride, there's no reason to build more Skunkworks elsewhere.
Remember that prototype units get a morale bonus, so makesure
your prototyping bases also have Command Centers,
Aerospace Complexes, Naval
Yards and ( as it becomes available ) the Bioenhancement
Center. This will mean your prototype units are not only reasonably priced,
but also extremely effective in actual combat.