Have you looked at hydro demolition? In the inset on the web page posted below is pictures of a similar project to yours
http://mmwaterjet.com/hydro.htmhttp://mmwaterjet.com/hydro.htm
Are you going to live in it? It is Cheep insurance, Go with engineering. Whats a few hundred more dollars, compared to the total investment of the house?
I would get it all in writing. I was a P/M on a job site some time back, and was amazed at how fast the sales people of some suppliers would try to make a sale at any cost. If they will stand behind it at all cost's, then let them do the job. If not, have you considerd precast structures? Might...
I have a dilema here, In the past I have always backfilled my walls without using top restraints on the walls, and so far have neve had a problem, but I want to stress that great care was taken to monitor the wall on backfill, to make sure no bowing or cracking was hapening. Here is my dilema...