Hello. I am preparing for an audition and suspect that I will be playing on a synthetic marimba. The piece requires both ends of the dynamic spectrum and im not sure what would give me a decent sound? any ideas would be GREATLY appreciated, thanks!

I'd go with Innovative Percussion's Soloist series. Also if you're playng on a yamaha accoustalon instrument, you should know that usually a mallet will be softer than on rosewood. Pretty much anything works though, except I'd stay away from the MArk Fod mallets for a synthetic instrument because they come off mushy and just dont sound great (as opposed to a rosewood instrument where they rule hard!)