Thanks for the follow-up :-)
I’m not seeing any significant lag there. It does appear to be loading about 200ms slower than average across other s2Member® installations though. Do you have output compression enabled at the Apache level? That would cut things down a bit further. It appears that you’ve implemented this already.
Have you made any modifications or added any MU plugin files to your WP installation?
Even with that extra 200ms, your latency on this is not that bad. s2Member® is going to increase load time slightly, if it’s JS/CSS files are included. No way around that. If you would like to optimize things further though, you can selectively load s2Member’s JS/CSS files if you like.
For CSS, please see: http://www.s2member.com/faqs/#s2-faqs-stop-loading-css
Here is another way to completely disable s2Member’s JS/CSS inclusion.
Create this directory and file:
/wp-content/mu-plugins/s2-hacks.php
( these are MUST USE plugins, see: http://codex.wordpress.org/Must_Use_Plugins )
http://www.kevinleary.net/faster-wordpress-move-javascript-files-footer/