Um..I've done the extension 1 papers upto 1990 and after a couple times you get pretty sick of the questions.
I don't think this year's paper will be that difficult. That said, I don't want to lower my guard like I did for extension 2. T_T"
My advice, don't worry about how difficult the exam will be, just focus on making sure that you get the easier marks because if you LOSE them, they will be MUCH harder to regain later on, ie. if you lose a few marks from careless errors in early questions, earning them back in the later questions is much more difficult.
All in all, just remember your formulas, think slowly and carefully and don't make up your own rules; maths is a subject where if you follow all the rules you will most likely get to the answer. I guess it all ties down to experience and how much you've prepared.
Now I'm just rambling.