I am bumping this post to elaborate my message. I am making a feature request for SIFT to MPE. That would mean, for example, when you are in the Polysynth alg., it would be cool if you could send out MIDI Polyphonic Expression to an external synth that receives MPE. Since guitar synths need independent pitch modulation to behave naturally, this would be the ideal route if you were looking to use your guitar to control an external synthesizer.