I still have the 3g issue. Sometimes mine comes back, sometimes it doesn't and I have to go onto airplane mode. Not everyone is having this issue it seems though, we're just the unlucky ones.
From recovery I'm not sure how to delete them, if you're using rom manager there's an option to manage the backups you made there, including deleting them. You should be able to go directly to the sd card to do it too.
The wipe data/cache isn't in the partitions menu, at least in clockwork, not sure about spr, it's in the main recovery menu. Some people do a data/cache wipe with every rom update. I only do it when I'm switching roms, like going from ud to liquid, and have never had a problem.
Sent from my Droid using DroidForums