buying a 370 from a private seller? is this a good idea?

Astrosfan

So, i found a guy who is selling his 370 on craigslist. It was his weekend car, has all service records, 15k, sport, base, ect...
Hes asking $27,800, which he saus is under bb value.

I have always gone to a dealer to buy a car and was curious on the process to buy a car from an individual, especially one this expensive.

Is there more room for negotiations?
Is this process complicated? going to the dmv, ect...

Obvisously, i would get the car checked out before purchasing it, i would probably take it to a nissan dealership and have them take a look, cost??

im really uncertain on how all this works....

Thanks!!