Extending basement as part of Unit 1

[Georges A.]

Hi everyone!

I am based in East Boston and I have a semi finished basement in a 3 Multifamily that I would like to legalize and make it part of Unit 1.  I have been struggling to find someone experienced who has done this before that I can rely on.  It feels that all the Architects and Contractors that I spoke with had different ways to tackle this project and I am worried that this could land me in a open-ended and very costly project.   I already checked w/ the Building department and they told me (informally) that there aren't any major issues that could make the project unfeasible. 

Does anyone know a general contractor who is willing to take on this project but has done it multiple times before (in Boston)?

Thanks in advance