Electric Panel Upgrade and what else?

I am doing a renovation in West Harlem to my 2 bed, 1 bath co-op apartment on the 2nd floor. Total remodel of kitchen, adding an outlet for dishwasher, stove (which will be gas fueled top), and one additional outlet over counter. All other outlets (2 others) existed or were relocated when I removed a wall. The Contractor added 2 new outlets in a laundry area we created for W/D, and 4 or 5 other... [more]

I am doing a renovation in West Harlem to my 2 bed, 1 bath co-op apartment on the 2nd floor. Total remodel of kitchen, adding an outlet for dishwasher, stove (which will be gas fueled top), and one additional outlet over counter. All other outlets (2 others) existed or were relocated when I removed a wall. The Contractor added 2 new outlets in a laundry area we created for W/D, and 4 or 5 other wall outlets throughout the unit. I have an old electrical panel which my contractor replaced because some of these additions and devices and outlets (ie. window air conditioner, new w/d, dishwasher) needed to be have their own dedicated circuits and there just wasn't enough room in the old panel. We upgraded it for more breaker service, and there is a 40amp breaker in the basement that services each unit in the building. All the other units in the building operate well on this service and they have roughly the same amenities which other owners installed over the years. I am being told that the old breaker panel has a wire gauge of #8, but it should be changed to #6. Do I need to do this, and what how much work does this mean? I do not want to inconvenience my neighbors more than necessary. I am pretty lightweight energy user and all the devices will be Energy Star rated. [less]