matthewj,
With just two days to go before the exam, there isn't too much more you can learn in terms of concepts.
I will give you the same piece of advice that I give each of my students two days before the exam:
You have already done what you could, and this is too late to build concepts. Use this time to clear any doubts you might have had during your presentation. If you have done that too, then spend this time making sure you have the memory portions of the test down pat. The memory portions are the portions which you must learn and remember, rather than apply.
Some examples are:
Idioms (SC), Geometry formulas (do the diagonals of a rectangle bisect?), and P&C formulas.
Finally, before you head to the test center, make sure you read instructions in detail and don't forget any key documents at home. All the best!