If you live where I work, this is what could happen,
your listing agent would have to look into the property file at the Inspection Department to see what is legally there as well as the Assessing records. (Assessing records do not say what is legal, they just show what is there for assessing only.)
If your agent chooses to sell your property knowing that the work was done without permits, then they would be liable.
Now, lets say you sell the house and the new owners decide to do some work in the basement, say replace the heating system, their plumber would take out a permit. When the inspector came to look at the work and found the non permited work, I would be notified.
I would contact the owner and try to see if we could get the work "permitted" and if the owner is not willing to do that, I would send the property owner a Notice of Violation and we could end up in front of a judge asking to have the work removed and ask for fines.
Oh, The local Electrical and Plumbing Inspectors will probably make the new owner remove some of the work you did, (like the drywall so they can see what you did.)
Are you starting to see where your name might come up!
Another thing, in the worst case. Let's say your wirering causes a fire and the house burns down, someone dies, do you think the insurance company will come after you to collect the money they had to pay out? I see the insurance agents in City Hall every now and then looking at property records.
My advice to you would be to see if you can get the work permitted!