tjwasiak I think that would work, but some tweaks would need to be done. I have not do it, just I remember my M383 to ME7 conversion plans. In terms of wiring here I left an info I collect in the past. Other case is software and maps. As you mention HFM5 have reverse flow measuring capacity, that is 0-1V. Other thing to take in account is that HFM5 linearization map is 512 size vs 256 for HFM2. Also offsets are different. Just my comments.....

Sorry if about if I do not understand, are you going from HFM2 to HFM5? I mean an HFM5 MAF with an old DBC ECU like M38x/M592???

Yes I would like to change type of MAF keeping older ECU (it is not even VAG car and it does have pure 8bit Motronic). I know it is easier just to swap the housing but stock intake in my car is built so it is next to impossible - it should be possible to connect MAF to air filter (but will have to find a way to mount IAT sender in silicone 90* elbow) but it will not be possible to connect MAF output with rest of intake system which I would like to keep stock at least for now.
The idea to move to HFM5 MAF came from the fact that 1.8T 3" MAF is capable of measuring up to ~1050kg/h (at least according to stock TT 8N0906018CB file I checked). I have S3 MAF housing and it will perfectly fit into my intake and I just wanted to know if despite the known issues it is going to work.