What it has done is improved your score in a few areas.
http://gtmetrix.com/compare/x3r3SsIp/6uFU7ZYI
Your webpagetest score is also much better than it was previously as well now.
http://www.webpagetest.org/result/130125_G1_3JM/
Although webpagetest archive results are a bit harder to find..
If you still have that custom htaccess, something is still not allowing you to properly cache images it looks like and it could be nginx is my guess. The only stuff that should be failing is external resources.
http://www.webpagetest.org/pagespeed...run=1&cached=0