at idle it should be around 19-21 in Hg MAP, and as a result, fuel pressure should be 40-42 depending on vacuum and accuracy of gauge.

IIRC, the best way to check fuel pressure is at idle with the vacuum line off, should jump right to 50-52 psi.

That price on used MAFs is ridiculous. Do they come with year+ warranty at that price?

I believe I have two or three sets working factory MAF/IAC/TPS for this reason.