OEM was 17", I downsized to 16" wheels which is normally the snow tire size. I like the thicker sidewalls / smoother ride, plus I really liked the look of the Drag DR34's. It's the family hauler.
Had a question about your pedals, were those OEM or aftermarket? If aftermarket, where did you get them and did you have to do some drilling on the dead pedal (the one on the left, where you just rest your left foot)?
Feel free to answer in this thread, or on the aftermarket pedal thread in the Mazda5 subforum: