$375 from Guhl. My 2010 has an Area P slip-on; Fred Harmon worked with Guhl to optimize the maps for a CS One slip-on, so I requested the "slip-on" map. I don't know if they have a map for 4 into 1 pipes. I also asked for the 155 mph speed limiter to be removed (don't plan to ever exceed 155, but at least my bike resembles the ungoverned 2008 and 2009 bikes). As to performance, there are threads and some dyno charts posted here and on the other forum (search for "Guhl" and "ECU reflash"). The reflash was worth the investment. The dyno charts for Guhl reflash show about 15% increase in HP and torque below 5k RPM; above 5k there is not much change. I definitely notice the increased low end grunt.
The one additional thing I would ask for now pertains to the ECO mode. It is my understanding that ECO mode turns off at 80+ mph. I don't know if Guhl has worked out a way to override this "feature", but on the highway it would be nice to travel in the 75-85 mph zone without ECO being engaged/disengaged with speed fluctuations (although I have to admit that I don't feel the bike transitioning between modes).
