Yes, please see details below regarding hooks/filters built right into the s2Member plugin :-)

Hacking s2Member® Via Hooks/Filters Advanced

If you need to add custom processing routines, or modify the default behavior of existing processing routines; please use an s2Member Hook or Filter for WordPress. Hooks & Filters give you the ability to "hook into", and/or "filter" processing routines with files/functions of your own—instead of editing the s2Member plugin files directly. This way you won't need to merge your tweaks each time a new version of s2Member is released.

What Hooks/Filters are Available?

There are more than 1000 Hooks/Filters spread throughout s2Member's codebase. While we work to document each of these, you can search our Knowledge Base for tips/tricks. Also, you can search the s2Member source code for do_action and/or apply_filters. This can also be very helpful. In fact, before you integrate with any s2Member Hook/Filter, it is suggested that you first see how it's used in the source code; i.e., to gain the insight that is needed for a reliable customization.