I know in the mid 2009 year they changed coolant tank because there were issues with the float but I was curious if that's where they got the extra quart difference. In the 2010 model specification pdf under changes coolant capacity is the only thing that comes up.

 

That's a good question. I don't recall reading anything about that, so I'm pretty sure if there was a change, it was insignificant.

 

The 09-11 has a larger radiator. The coolant reservoir looks identical(I have an 09 R3 in the driveway next to my 04') to the 04-08.