config files: bin vs cfg file and local vs all?

[asinshesq]

Hi. I've got a few questions about the config files that the phones allow you to export and import (I have t46gs, t20s and w52ps but I think my questions are more general):

1. I know the bin file the phones allow you to export/import includes wallpaper graphics (pics) as well as config setting info...is the ONLY difference between the information in the bin file and the information in a .cfg file the wallpaper graphics (pics)? In other words, if I export all configuration file as a cfg file, is that a complete backup except for the wallpaper graphic?

2. What's the difference between exporting all configuration vs local configuration? I see that the local configuration .cfg file has far fewer lines, but what's the rule for what gets included in a local config?

3. From what I have read elsewhere on this forum, I gather that if I upgrade to firmware 28.80.0.70 it's a good idea for me to factory reset the phone. If I do that, does it defeat the purpose to then import my old cfg file? I spent a lot of time getting the phones configured to the way I like and would hate to lose all that info.