I have an 07 SEUC, 27k miles, have always had a vibration in 5th gear when under 3000 rpms and at any speed in 6th gear. I really like the bike and have been comfortable on it by simply riding around those problem areas. I have had several "experts" ride it and they all agreed that the vibration was there but did not really know how to cure it. I always felt that it is geared too high and needed a smaller front sprocket or a larger rear one.
This last weekend , I purchased the IDS kit and installed it myself and that eliminated the vibration, the bike is now as smooth as my 05 seeg. The installation was pretty straight forward, if you don't have a press, however, you need to have the dealer press in the bearing before you take it home. I still feel that the gearing should be a little lower and I may install a 31 or 30 tooth front sprocket, just to give it more pep.
I have read about some owners having a vibration at 2900 rpms in any gear, which is more of an engine problem. It will be interesting to see if the IDS will help that type of problem.