Another note I'd like to add about the importance of a proper map sensor is the consideration when tuning for aux fuel.
The fuel controller works off 2 inputs. RPM and MAP voltage. If you have not seen a pressure sensor operate near its limit, you will find that it becomes very unstable as it approaches its limit. With that being said, when using the oem sensor, and running 25+ psi to redline (with a larger turbo), the resolution of map sensor becomes very erratic. You can actually see voltage jump around between 4.6-4.75v on a 5v sensor. This is not ideal for tuning the aux fuel system.
Replacing it with a larger scale sensor allows you to operate in a more appropriate range of the sensor, making aux fuel tuning much more simple and precise.