You can take this advice or leave it, but my advice would be to go to Orange County or Riverside County for a Nissan. Here is the reason: Every Nissan dealership in San Diego County except for Pacific Nissan, is owned by Mossy! That's right they are all owned by the same company.
The one thing you can do to avoid going to ORange County would be to use the Costco purchase program. They negotiate great prices. See my response to the thread below as I detail out how positive an experience I had and I didn't even get the car.