additional map sensor
What I am going to note I have done, but for completely different reasons.
You can add a second MAP sensor and pull the low voltage off of the original map sensor.
You can run your edge thru the second map sensor only, and let the original sensor run the factory (or smarty modified) computer.
You will have to make a housing to mount the second sensor in that ties into your intake system.
I am not saying it will work with what you are trying to do, but it works great for my use of being able to tell the juice a different boost than what the engine is seeing.
West