Agreed - When you start to do upgrades (and you will) to the intake, exhaust and computer. The 7.3 will naturally boost at higher levels. Stock, I believe the 7.3 is throttled back to 17PSI boost; however, it is capable of 26-28PSI boost. This is a great increase in performance; however, without the MAP-Maximizer the MAP sensor will see the increased boost level and trigger the computer into a "limp" mode as if there was a mechanical problem and trigger a code.
The Maximizer removes the excess boost levels from the stream into the MAP Sensor in order to avoid AMP issues and the "limp" mode.
Works like a CHAMP.