Ok heres what ive found to be the differences between the games.
1. Blood, The blood has been toned down in the Aus version. When you kill someone in the uncut version there is a blood pool that comes from under their body.
2. Hookers, In the cut version you only see the rear number plate of the car. Where as in the uncut you have 3 choices on what you want the hooker to do and you can see in the car.
3. Language, It seems the cut version has the language toned down a little.
Thats all ive found so far, Ive been playing the cut version since release and just started the uncut one today, ive continued on from where the cut version left off. So i can confirm that your save will be ok when you switch versions.