5)Is better to get a owner permit to do that work or contractor permit or do it with noo permit from the city?

I'm flying in Thursday afternoon, arriving at the hotel about 4:30-5PM ish, flight times permitting.

He says he'll take $200 off the job if I get the permit.

Permits?

I would warn that the non-permitted garage conversion could give you trouble with the city inspector so i would be very leary of doing this particular deal with the info you provided.

In my leases I clearly state that tenants may not run a home business, I would recommend you do the same unless you have worked out an agreement with the tenant that allows them to run a business and in that case, spell out exactly what business is allowed and that no other business is permitted.

The co-op does not permit rentals, so if things were delayed it might cause a problem.

We finished our basement 5 or 6 years ago and got permits and inspections and are paying taxes on it.

Only exception to that is the fact that you say it is already 3 layers - in many places only 2 layers are permitted by code.

Your budget and whether or not you have someone to pull permits for you could be factors.