I'm prepping my system to do this exact upgrade.
It's going to be an upgrade from Mountain Lion.
Question for you guys:
I have a time machine backup on my NAS of my current Mountain Lion config (I excluded the Extra folder where the Chimera's bootloader files are kept, and have also excluded the Extensions folder where the system Kexts are kept) I've done this in part because when I upgrade and attempt to migrate my apps, user configuration, music, etc the drivers that have been added or modified by Clover will not be overwritten, and also will not include Chimera. I've read that no matter what you do (ie. migrate apps over) the migration assistant will also fudge around with the kexts from the backup.
So this is what I have going so far.
I plan on installing this fresh with another harddrive, then after clover is configured and the system seems stable, migrating over from a Time Machine backup. I have so many applications that I have configured to run a certain way, my itunes library that took me ungodly man hours to organize, p2p programs with specific lists that need to be kept running, etc.
My question for you guys is if any of you have done something similar. I have no idea if this is going to work and finding information about this unique upgrade and migration is not easy.
Any thoughts would be welcome. I'll buy you a beer if you come on down to the 6