There is another FAQ by @cdep.illabout but that is slightly outdated.
Q: Can I flash CM11/12 to the SC-03D
A: You can. See the following posts.
Q: How can I sim unlock the SC-03D?
A: Follow the guide on the next post
Q: Where can I find original SC-03D firmware if I need to return the handset for service?
A: You can find official firmware at Sammobile
Q: What is the highest android version officially available?
A: The final firmware released for the SC-03D is OMMP5 (Android 4.0.4 Ice Cream Sandwich)
Q: What is the highest android version available by custom ROM?
A: Cyanogen MOD 12 is running on my SC-03D. Though, it is not very stable.