There is a big advantage in being located close to the center of Cagliari but not muddled in the crowd: the parking of your car is never a problem (and reaching the heart of the city is a snap via public transport or even via foot).
We use two main locations when parking our cars: Via Noto and Via Libeccio. Both the streets have plenty of free parking zones, the first one being the biggest one.
The two main parking areas are very close to the B&B, around 250mt in both cases. The zones are safe and we use them all the time.