quick question

view story

http://androidforums.com – I got a samsung galaxy s3 that i rooted it's a SGH-I747 (AT&T) and my phone has Android version 4.0.4 on it. I was wanting to know can i put install a app on it and it called synergy ROM. It shows android 4.1.2. On the galaxy3root(i can't post links yet but that's the site's name i seen it on.) But i was wanting to know will it hurt my phone if i installed it or not? I was also wanting to know where can i find a 4.1.2 rom if i need it? Thanks! (General)