Most likely, no. The site you are getting the feed from would have to send out the complete text and they don't want to do that because they want people to come to their site to read the full article.
Could be. Like I said, it depends ont he feed. They need to actually send out the full text in order for you to post the full text. I do know that there is no default setting in vbulletin for you to turn on/off in order to post the whole article.
According to the manual - Editing RSS Feeds - you have these fields to use:
Quote:
Within vBulletin, we allow you to access only specific parts of the RSS. The fields you can use are title, description, link, id, date, enclosure_href and content:encoded
These fields of information can be included in the templates using the simple format {feed:fieldname} where 'fieldname' is the name of the field whose contents you want to insert.