Need input on rear master cylinder purchase for S2R 800

[EEL]

My rear master cylinder is shot on my 05 S2R. I have to replace it. Its an easy enough task so I'm not too worried about the installation but I have a couple of options.

Yoyodyne has 2 options in stock in the style that i need.

a) I can get a 13mm bore rear master cylinder
b) I can get an 11mm bore master cylinder

Questions:

1) Whats stock on an S2R 800? 11 or 13?

2) When comparing both master cylinders, whats the difference in pedal feel and braking power when comparing one to the other. Please note that both are OEM brembos.

I'm willing to take recommendations or which option I should get from you guys who have dealt with this before.

Thanks in advance.

[Howie]

Your stock master has an 11mm bore.  The 13 will give you a shorter stroke, but more pressure would be required.

[EEL]

I figured that was the case, basic hydrolic theory states exactly that. I'm leaning toward the 11mm bore. The last thing I want is to lock up the wheel too quickly.

Anyone try the 13mm bore? is it worth the purchase?