You might check on just renting the GPS with the car. Otherwise, go to your GPS's site and download the Europe maps, but beware, they may cost almost as much as a whole new unit. For instance, Spain/Portugal maps for my Garmin are $69.99 either to download or on SD card. I DO see these on eBay for $25, but haven't tried them.
We really enjoyed our trips to that area. We rented the car from Carjet in Lisbon. It came from the Budget desk at the airport and had enough dings and nicks that we didn't worry about getting a few more while parking. There is a great tollway N.& S. in Portugal, just remember to get a ticket at the first toll booth.
Prices in both Port. and Spain are reasonable. We stayed at a TS in Albufeira, Pt. and W. of Barcelona. They had a bottle of local wine on the counter and had more in the office for 1 Euro/bottle! Are you taking the car to Morocco or just day-tripping to Tangier? There is a good Rick Steves episode that will give you a good overview if day-tripping. You can view it online. Different trip, but we spent 3 weeks in Morocco, including tent camping on the Sahara with the desert people. Wonderful experience.
I don't know what details you are looking for, but if you ask, I'll try to find an answer.
Jim