OK, First of all. It is much better for you to run the upgrade through the launcher of G3 itself than to d/l and install it externally from my past knowledge with games.

When you get G3, install it and then register and then run the updater, it will automatically run through and get every update available in order so you don't miss anything. About add-ons, I am not sure, I just got G3 on X-Mas and I to am looking for that answer.

Idle-Up is the top left switch on the Interlink controller, its a 3-way switch. Collective is the same for your real heli, except on the Sabre it is throttle and not collective. Does the same thing though, makes heli go up and down.

For either of the Tx you listed, G3 comes with cables necessary for them. Yes, they do plug into the Interlink controller.

Now, any mistakes I've made, another helpful person will come along, particularly jaafit, and correct me.