Best way to upgrade 4S to ios 7?

[G-TEC]

I've got the latest ios6 on my 4S. I usually just do a OS update but this time I want to restore to factory settings to clear out any junk that may be slowing my phone down.
Would the best procedure be to restore the phone (which would be ios 5), then do the ios 7 update, and then finally restore my phone data from the backup file?

If I just did the update to 7 and then the restore (to factory settings), does the restore clear everything back to ios 5?

Thx a bunch.

 

[xConnerIdan]

I've got the latest ios6 on my 4S. I usually just do a OS update but this time I want to restore to factory settings to clear out any junk that may be slowing my phone down.
Would the best procedure be to restore the phone (which would be ios 5), then do the ios 7 update, and then finally restore my phone data from the backup file?

If I just did the update to 7 and then the restore (to factory settings), does the restore clear everything back to ios 5?

Thx a bunch.

Yes, exactly as you described.
If you want, just backup your contacts/apps/SMS on iCloud, but then again, it's option.