another succesfull story
eMMC died in my i9300 and after countless hours of trying to revive it and finding this thread I finally decided to upgrade it to i9305, so I ordered tested-as-working (wanted to be sure that it was fully functional so there would be no doubt if I messed something up in the process) i9305 MoBo for around $25 and as soon as it arrived I started the process of careful dremeling the metal pieces. I used thin clear office tape to cover holes exposing display's PCB (it was pretty tricky as they are directly next to places I was working on, in hindsight I think it would be better to cut out mask from paper to cover everything except place I was working on) and used medium-sized flat-headed screwdriver to cover delicate chips from accidentally slipping dremel head and damaging it. After evening out frame "separator" to same height as its top-end and taking out little off metal near bottom-left screw hole (look at the pictures in first post on the second page of this thread) I put everything back together, but SIM couldn't be recognized and corner near back button was getting pretty hot, so I put a piece of clear tape on demeled place near bottom-left screw hole, which soled the issue. Everything is working except of LTE, which is working, but not very reliably, still sometimes reaches better speeds than 3G.