I'm suprised no one has mentioned the timing restraint for the exam? Are all you lot on extra time or something?
If you finish the paper 5+ mins before the end, you really haven't done amazingly. Yeah you could get an A* if you're a really fast writer but it won't be a strong A*.
If you screw up on timings in the exam, expect a grade lower than you hoped for. Also remember how small the gaps between the grades can be.
In other words DO NOT RUSH IT but also TAKE YOUR TIME. Practice makes perfect, not matter how much of a good writer you are - it's not going to help you if you miss out a question. Again if you miss out on a question (particularly q6) you could potentially get up to 3 grades lower than wanted.