Join Date: Jun 2005
Location: Jacksonville, NC 28540
At your size the 600s are going to seem a bit small no matter what. The manufacturers have begun putting stiffer springs in them, but ergonomically they will seem a bit small. My track bike is a 05 model R6, and I've made a lot of changes in the chassis to accommodate my weight (pretty close to yours).
That being said, the 600s are a great choice nowadays because of the power they put out, and the chassis' are phenomenally well handling. With the comparisons being so close, it's really a matter of sitting on each, and finding a color and features that appeal to you. Even on the track they are all so close to each other, it's typically the rider that makes the ultimate difference.
1991 FZR 1000 - built 1040 with race cams, Akrapovic full exhaust, and mild suspension work
2004 YZF R1 - Graves full exhaust, velocity stacks, BMC race filter, and Power Commander. Rear Ohlins. Forks rblt with Race Tech springs and Gold Valves.
2005 20th Anniversary V-Max (0098/2000) - T boost,
2005 YZF R6 track bike - Graves full exhaust, Race Tech suspension