If i give the leaked ICS rom a try and don't like it, do i simply just use a nandroid to get my phone back the way it was? Would i also have to flash the old radios as well, or is that part of the nandroid? Thanks.
Yep, just backup your stock ROM, and then you can flash back to it whenever you want. I'd try the radios from the 2.11.605.19 OTA first. The newly leaked radios gave me and plenty of others a bad case of the reboots. Plus, if you decide to go back to a GB ROM, you won't have to mess with the radios.
If you decide to try the new radios, be sure to remove the file from your sd, or rename it at least, right after you flash them. Same goes for the. 9 radios.