Yeah, dont relax too much, when I took phase 4 I had that attitude of 'hey I have just seen a large group of 20 people at phase 2 peel away to 2 people including me, I rule!'
The day after phase 3 I wandered into the Kingair and failed miserably, probably due to my own naive arrogance! I eventually saw it as a good opportunity to get myself into the right frame of mind and resat it with a heightened respect for phase 4.
At the end of the day it is still an assessment, and although it is fun, its probably not best to look at it as some sort of reward for passing 1, 2 and 3. You can still fail, believe me.
Not trying to be negative, as I understand it and as has already been mentioned, the chop rate is low at 4, the right attitude and the right frame of mind is essential for this stage, as it has been for the previous stages and it should still be treated with the same respect.
On a lighter note, one advantage to failing phase 4 first time was that I got to play with both the Kingair AND the 737!! HA!!
Anyway good luck all!