I know some people did it and they are very happy with the results it's probably the best solution for catalysed buell models (>=2008)
http://www.twinmotorcycles.nl/artikelen.asp?aid=67
You can get that for approx. 1600€Here are the details of the stage 1 tuning.
Stock 2009 XB : 85 HP and 99 NM of Torque
STAGE 1 2009 XB : 98.2 HP and 106 NM of Torque.