Sit down and have a long meeting with whoever you decide to go with. I've fixed lots of mid-build **** ups before and holy ****, it takes more time than starting over about half the time. It is one of those deals where you need to draw a line as to where to stop "fixing" ****. My guess it will be at $55/hr shop rate x however long it takes, and double the number that you first come up with. There will be supplements.
The other thing is most shops won't want to put their name on the work because there isn't enough money for them to start over and make it all theirs. Tough situation for sure.