It's interesting that guys will hem and haw about spending $75 to prep for the FEX, but won't think twice about plunking down big bucks to take a practice (heavy metal) sim ride, in preparation for an interview that might or might not come, in an aircraft simulator that might or might not be the type that they actually get at interview time. I guess I just never understood the mentality. FedEx, and most other airlines are not interested in whether you can fly their simulator perfectly. What they are interested in, in my opinion, is: 1) whether you can follow instructions; 2) does your flying ability roughly validate your stated hours in your log book; 3) did you have a basic cross-check that allowed you to realize errors and make corrections; 4) how did you deal with deviations, both in your flying ability as well as your psychological ability to make mistakes and recover from them; and 5) how did you handle the stress of the sim ride itself.
I'm not saying that sim practice doesn't have its place, just that if you're currently flying and are proficient, you probably don't need another hour or two in the box. However, if you've not flown for a while, it's probably a good idea to get in there and shake some of the rust off your brain, in preparation for the sim ride. As far as FedEx goes, I can tell you, with no uncertainty, that the ride is a basic airwork ride, and that the guys who conduct those sims are first class and will make you feel at home, as much as is possible, with you knowing that if you blow it, you're probably not going to make the cut.

That said, relax as best as you can and cross-check, cross-check, cross-check. And good luck, and remember, there's no crying in flying.
JJ