After-market Plus Performance Package

Depends on what you want out of the tire.

I found 40psi to be a nice compromise between mpg, handling, road noise and comfort. I suggest 38-45psi depending on how smooth your roads are and how cold it is. The colder the temp the lower the recommended pressure to help with traction.

This assumes you are talking about the Primacy MXM4 which is the OE tire for the Prius Plus and Lexus CT200h.

 

I tried mine at 40psi but they were way to stiff and harsh. I settled for 36. It may not yield the best mpg but the comfort is still somewhat there.