The first owner of my '09 K13GT suffered from low-speed fueling issues where if you'd been riding down the highway for a while then came down an offramp to a light, the idle would be trimmed so low that the bike could die. BMW bought the bike back, then took it to a US-based BMW tech center and hand-tuned the fueling map as part of the overall investigation and development of a new K13GT fuel map.
That bike has run flawlessly for the past decade, in all weather and temp conditions without a single hiccup, despite my best efforts to kill it a couple of times.
So your options are:
1) Rev higher
2) New software from BMW dealer (latest fuel map)
4) Power Commander
4a) Power Commander with a custom dyno tune
I'd stay away from the BoosterPlug, as all it does is shift the incoming air temp signal to force the bike to run richer. It kinda works, but it's not smart at all...