Move a car to Spain as a none-resident

We have a house in Torrevieja and we are here sometimes. I am thinking about to have a car here as well. We wish to take my wife’s old car from Sweden to Torrevieja. She wish a new one in Sweden.
So, the question is if we can own a permanent car here when we are “non-resident” in Spain? What to do and how?
Appreciate all tip.