After lookin thru the files I found it! here's what you need to do to be able to have the intro text show up for non registered users then prompt them to register after they click 'Read More' as with a default joomla install. You dont need a second component!

In the files magazine.html.php & magazine.php is code to read articles from the database, this reads only articles available for a certain user level so you will need to edit the select query to read all articles from the DB by removing the C.Access..... condition from the WHERE clause. Do this in both files and there are a number of queries not just one.

In magazine.html.php you will find a line that reads
if(($hide_content_unregistered) || ($article->access>=1) || ($edition[0]->access>=1) || ($section[0]->access>=1)) should be 527 or around there.

remove the $article condition from there as well so you have
if(($hide_content_unregistered) || ($edition[0]->access>=1) || ($section[0]->access>=1))