Can I modify my Product Titles in the feed?

Yes, by using the concat rule command you can modify your product titles. To enter the command, please navigate to Manage Feeds > edit > open the advanced command box near the bottom of the page.
Below are a few examples:

1. This set of commands append ” – MyModifiedTitle” to all Product Titles:
rule concat(title," - ","MyModifiedTitle") as combo_title
setAttributeDefault title as $combo_title

2. This set of commands will prepend ‘brands’ to your title:
rule concat(brand," - ",title) as combo_title
setAttributeDefault title as $combo_title

Comprehensive Advanced Commands and examples can be found here