Hey Hows it going..

So i havent posted in a long time, finally got another rx7 CYM R1!! well my question is, i just moved to a higher altitude area, and i'll be travelling back to and from a higher altitude to a lower altitude.. My question is directly related to tuning, how does altitude play a part in timing advance/retad and afr's? I know the basics about tuning etc, just the altitude i wasnt sure, unless the map sensor reads the altitude and compensates for it, weather its a stock ecu or a power fc, correct me if im wrong..

THanks