I installed mine last week. My 2007 R12GS runs noticeably better. Throttle response is better and the bike accellerates harder when I open the throttle to pass. It feels like the bike has more power though I expect a dyno would not show it as it's on transient throttle.
It's a worthwhile mod for sure. My only complaint is the long time delay between ordering and receiving.
There are other similar units (minus the adjustability) out there, so if you are impatient like me they might be a quicker option.