Have a 2017 4Runner. Manual recommends 0W20. I live in Tucson, AZ and would like to run a higher viscosity, like a 5W30 syn. Manual leaves no room for alternates under different conditions except, for Puerto Rico only. Higher viscosities OK. A little confused? Is the Puerto Rico engine of a different specification or is it just gas mileage/environmental? Any opinions on a higher viscosity causing potential harm?