http://gyroperfo.com/en/index.php
It's a French site and the English translation isn't great, but enough to get a general idea of what it is. I'm sure it voids the Rotax warranty.
Any idea what they're doing to get additional HP? Think it's just overboosting by tricking the TCU? (I installed something similar on a my old VW GTI). Anyone ever tried it out? What are your thoughts? What are the major concerns?