Congrats!
As Speedbird said, make sure you know what you're supposed to know on forehand. You're not expected to know the plane before you do the course, but you are expected to know all the little rules about IFR flying, all the generic stuff: timings, how to fly various full procedures etc. It's a nuisance to know that you're being tested on the plane's systems if you're feeling that flying the procedures is taking most of your capacity.
Make sure there are no questionmarks about this and you'll be able to concentrate fully on learning the plane!
/LnS