Mags at Altitude

[WebMaster]

I can remember reading about the P models, who have pressurized mags. If they get to some altitude, they have to have pressurized mags to avoid, something. Mis fires. Those of us with normally aspirated Skymasters, if we get up high, what prevents those mis-fires? Can we get pressurized mags? What do the Turbo Skymasters use? I got my O2 system all set to go, and I want to get up to some altitude and catch the tail winds.
Thanks