Many thanks to Eugene Dementjev, the developer who recently adjusted the E-goods module to fully support Amazon Web Services. Since we've upgraded our web server to use a much smaller (yet faster) Solid State Drive, we've shifted all of our large files to the AWS cloud. This E-goods module's most recent update with v5.3.3.0 was very significant in enabling us to save server space while also limiting the access to valuable files (such as proprietary MP3s) to those who have made a purchase.
You didn't need the latest update if you had a smaller library of files to sell online, and were comfortable with storing them all on your web-server. This latest patch is -very- helpful for those of us who have less local space to work with, yet a larger selection of e-goods.
In order to make use of the off-site storage feature of either this "E-goods" module or the "Amazon S3" module, you will want to create a username and at least one parent group on the IAM section of the Amazon Web Services Console. In the "Permissions" section of AWS - > Users, you can then assign that username (and/or group) permissions for the groups AmazonS3FullAccess and AmazonS3ReadOnlyAccess. Under a neighboring tab, "Security Credentials," create an access key. Copy that AWS access key, the AWS secret key, and the S3 bucket name (which you would get from the S3 section of AWS) onto both forms for X-Cart's E-goods and Amazon S3 addons.
Once you have created the connection between your AWS account and your X-Cart store, you can upload files of nearly any size onto the S3 Storage service of AWS. Once you have uploaded a file onto S3, you can copy the URL of that file. Back on X-Cart, when viewing the corresponding product in the product editor, look for the Attachments tab. Select "Add file" -> "Via URL". Paste the URL into the textbox, un-check the box next to "Copy file to local server", and press the "Upload" button. This will not take much time at all, as only one row will be inserted into the xc_product_attachments MySQL table, and a corresponding row with the path will be inserted into the xc_product_attachment_storages table. That part is behind the scenes (now, because of this update), so you won't need to remember those table names anymore.