How to make box frame in basement wall

I am considering buying a house, but it has evidence that the walls of the foundation are cracked, and the whole house is supported on I-beam pillars spaced every few feet, all around all the walls of the basement. The cracks are filled in with a special epoxy filler and the basement was finished with walls in front of the I-beams to hide them. The house has been vacant and every time i went there it is dry. There is an engineering report from the company that designed the basement refurb stating that the work was done in compliance with all the proper codes and meets and exceeds the building code requirements, and all the repairs complied with thier design. The repairs were berformed by the builder following an engineering companies direction. There are building permit stickers in various parts of the house showing the repairs were also approved by the local town building inspectors. The house is owned by the original developer/builder. The development is about 10 years old and it looks like this one was used as the model unit/ offices based on the work they are doing to convert the interior back to a condition suitible for sale. What i am interested in knowing is, is the method of work i described ring a bell with anyone on what could have caused this level of work to require to be performed in the first place? Bad concrete, soil, movement, bad design, etc.. What is the risk in buying a house that has had this type of repairs performed? How long can something like this last, and if it is better and stronger than a poured foundation why aren't all houses made this way. What would be a worst case scenario down the road be if i bought this house and what could happen that i would look back on to regret? It is a really good deal and i hate to pass it up out of fear of not knowing the facts of how bad it really is. BTW, the selling broker will not put us in contact with the builder or the engineering company unless we show seriousness of intent to purchase with an offer. She claims that they are flooded with calls with everyone wanting to know more and the engineering report is all that is available unless they know that the person is sincerely interested enough to put in an offer contingent upon being comfortable with what they discover from the builder/engineering company.

My foundation is cinder block and the basement is a walk-out. The only windows in it are several hopper-style that are about 32x16. What I want to do is remove one of these and enlarge the opening vertically so I can install a double-hung window. The opening won't be any wider, so there's no concern about needing to replace the lintel block. What I'm not sure of is how to finish the ends of the blocks after I cut the opening, so the inside of the opening is smooth all around.