I am told that Mazdas are shipped with 45-55 psi in the tires. Part of the dealer PDI is to adjust this to the propor level. The reason for this is supposed to be that it allows the car to be tied down more securely. I have driven several driven several Mazdas before this was done and the car rides like a truck. If I notice that the car rides poorly during the test drive, I check the tire pressures and let them down to something near what is called for on the door tag. On the other hand, if the steering response is terrible, I check the tire pressures and if they are under inflated, I pump them up to the figures on the door tag. I usually spend the first few months trying different tire pressures and different proportions front to rear. Once I find a set I like, that is what I usually keep them set at. For the MP3, I settled on 34/34 psi. The front responses well, the ride is not bad (in Arizona) and I can toss the backend around if I want to.