What should I consider when cutting/making window in concrete foundation?
I realize that you don't want to proceed with the project but I thought I'd answer anyway in case someone else is curious. I am a licensed contractor and my company specializes in basement remodeling; we have done several window expansions or additions in concrete foundations. A few things:


You definitely need a permit for this project (though you don't need to hire a contractor) this is a structural modification and needs to be done correctly.
You definitely need a structural engineer to write you a letter after a site inspection stating his recommendations for keeping the structural integrity (when you get a permit, they'll require this any way.
If you are making a bedroom in the area you are adding a window to, you'll want to make sure that the new window you put in meets egress code for inspection/permit reasons.


Though you can support the new opening with pressure treated wood (according the engineers prescription, of course), most likely the engineer will recommend a steel frame in the newly cut opening. We use a 4"x4"x1/4" steel frame that the engineer signs off on. You can have one made to fit your opening at your local steel fabricator. (see pic below)



After you install the frame with bolts into the concrete and silicone sealant around the entire perimeter, the installation of the window is a piece of cake.