Seeking recommendations for design/build firm for brownstone gut

I am looking for recommendations for a good design/build firm or GC that can help me with a gut or near-gut of a brooklyn townhouse. Major internal upgrades needed, but hopefully very limited structural or exterior work. I am looking for somebody that can work within a budget and tell me what is and is not feasible without triggering total DOB hell. There is currently no CO, the house is zoned as a two-family and we will want to maintain it as a two-family. Please let me know if you did a similar job and recommend (or do not recommend) your firm/GC. Thanks in advance!