Airtac adapters need to use AEG mags with a significantly higher spring strength, cheap AEG mags are almost always not up to snuff. PTSEPM1/1S definitely work (what the adapters are designed around), older EPM's (Gen1) do not. Mags i've tested that do not work, anything made by KWA, Specna, Ares, Classic Army. Some CYMA's can work, but only more modern ones, G&G are hit and miss - if they have the follower that goes outside of the mag lip, forget it, G&P Troy mags will work, but you'll have to part fill.
PSI wise, it'll depend solely on if the adapter in question has a built in expansion chamber, if it does you will be able to run it on 80-100PSI. If it feeds the line through the adapter direct to the output valve, it won't run on anything less than 120-130PSI, and probably more realistically 140-145psi (and if you've got heavy bolt, or other heavy recoil mods, higher PSI to overcome mass).
Edit: Looked at them. Neither variant of airtac for VFC M4 has an expansion chamber, so its higher PSI almost certainly.