Master cylinder rebuild on 2005

Its come to my attention that 2004-5 front master cylinder is different from the 2006 and up. So a rebuild kit for the 05 is nowhere to be found but with a modification a kit for the 06 can be used. Has anyone done this and what all is involved? TIA

I have had early master cylinders bored and resleeved at Brake & Clutch shop to suit the bigger 15.875mm diameter piston that is on the Roadster and Touring models.
That gets rid of the spongy lever on the early model master cylinders.

Kit part number is
Piston Set, M.Cyl 15.875 T2020294