You will find all the tools for editing here
FIFA 13 How To Thread
http://www.soccergaming.com/forums/showthread.php?t=175659
Use File Master 12 to browse to your Fifa 13 folder, the boots are in data3.big like so,
left click on the Name Tab to sort out the files alphabetically, scroll down to shoe,
select all the shoes (338 files) remember the address (data/sceneassets/shoe) like so,
Export the files anywhere you want. Like so,
Do not use Creation Master to import textures into the boot file it has some bugs,
only use it to preview the boots and check the id`s (boot number, boot model)
There are 2 files for boots, example
1)shoe_163.rx3 (the boot model) this is the Nike Mercurial Vapor IX boot model and
2)shoe_163_0_textures.rx3 (the texture "container")
Open RX3 Master, open the texture rx3 (the texture "container") like so,
Replace the three files using the import button
File 0 (texture/skin)
File 1 (Bump Map Shader)
File 2 (specular file/Reflex) like so, and save the file.
EA`S default textures are low resolution 256 X 256,
someone here (moddingway) hex modified it to 512 X 512 resolution (only the textures).
You`ll need the modified RX3 file. You will find it here
2GK Boots - Double Size Textures
http://www.soccergaming.com/forums/showthread.php?t=176107
Once you saved the file, copy them to (FIFA 13\Game\data\sceneassets\shoe) folder
and regenerate with Creation Master from the tools menu like so,
click yes when prompted.
Some links to help you with editing
FIFA 13 How To Thread
http://www.soccergaming.com/forums/showthread.php?t=175659
FIFA 13 IDs
http://www.soccergaming.com/forums/showthread.php?t=175345
Revolution Mod 13
http://www.soccergaming.com/forums/showthread.php?t=175176
Revolution Mod Manager 13
http://www.soccergaming.com/forums/showthread.php?t=176871
Good luck editing your boots, Bye.