if you can moniter the afrs, you could run 3psi fine, people need to understand maf systems better, they only know airflow, not pressure. running the supercharger just raises the airflow so its on a different spot on the map, the mazdaspeed tune would be fine, it just has more flow at an eariler rpm and the ecu is tuned for that, for safty (supercold mornings denser air more flow)
3psi in the alps is like normal air on the coast, altitude changes air density....