I'm still running 9 of these on the MO-RA3 and so far no issues, i don't hear a buzzing noise at 1200rpm or so, they are literally dead quiet.
Screws are available from a certain online retailer, i just got a few packs for spares. It's unfortunate but radiator manufacturers haven't standardised the screw hole size or it would be so much easier.
Thats good to know - my screws are on the way from China - only place I could find black M4 30mm with philips for a reasonable price (online).