quick question regarding 3.1.3 and 4.1/4.2

[vse]

I have a 3gs on 3.1.3, i checked saved shsh on tiny umbrella and it says i have files saved for 3.1.3 up to 4.1

If i want to upgrade from 3.1.3 to 4.1 do i just use tiny and start tts?

Also if i do update to 4.1 can i just go back to 3.1.3 if i want too using tiny?

And last restore means i lose everything or do i keep the files i have on my iphone?

[j3st3r]

yes you will lose everything with the restore, sync before the restore to get your contacts, pics, etc back. pkgbackup from cydia will back up your cydia apps as well, as for using tinyumbrella yes start a tss server to restore, use shift+restore in itunes and select which firmware you want to restore to, if you need an unlock you will need to use a custom firmware and redsn0w to restore to 4.1 so that you can keep your unlockable baseband, instructions for that are here