Research?
Hesco Adj. FPR - A while back I spoke with a Hesco tech and it also works on the 4 cyl.
I don't know know the reason the stock ECU cannot read the GM 2 Bar MAP, but it would not work on mine.
If you read the product info on the SplitSecond site you will notice that the AlC1, FTC1 and PSC1 come with
their R4 software which will walk you through how to set up the Maps. There is also a Tuning Guide you can read to help you set up Maps, you will find it near the bottom of their index on the left side of the page.