I ask because I'll be wanting to get one at some point, and I might have to jump a few hoops to keep my unlimited data, but I'll be kinda screwed I guess if my Note 2's SIM doesnt fit the Note 3?
The Note 3 uses a micro SIM, so if that's what you have in your Note 2, then you don't have to do anything. Even with a different SIM size you could cut to the smaller size and use an adapter.