Nik, just to clarify what I thought might be a typo, have you only had this bike for 6 mths, and you have already put on 8k kms on it??!! Thats pretty awesome!
As far as upgrading, does the idea of doing all of that highway riding in a relatively cramped position do it for you? The 600 s/s bikes are built for the track, and while they thrive in the twisties, what is going to be the majority of riding that you will do? All of these need to be considered, especially if you pull the trigger, buy a 600 and then hate it after a couple of months.
Don't get me wrong, I'm not trying to steer you away from what you think is the right bike for you, just make sure you do make the wrong uninformed decision!
As far as upgrading, does the idea of doing all of that highway riding in a relatively cramped position do it for you? The 600 s/s bikes are built for the track, and while they thrive in the twisties, what is going to be the majority of riding that you will do? All of these need to be considered, especially if you pull the trigger, buy a 600 and then hate it after a couple of months.
Don't get me wrong, I'm not trying to steer you away from what you think is the right bike for you, just make sure you do make the wrong uninformed decision!