Mine is vibey around the 4500rpm mark. Not so much that I'd think there was anything wrong with it though. And like you say - smoother vibes and loads of pulling power above 5000rpm. Mine's an '08. It could be a different software version and I don't know if that would make any odds anyway. I've heard that they've tweaked the balancing on the 08 engine. I don't know if that is true or not. Like you, I've not got anything to compare with as this is my first GS. If you've not resolved the problem yet at the time of me writing this, why don't you go and test ride some dealer bikes with a view to 'buying' one and see if they run any differently.