Server response time

Trying to improve server response speed. Hummingbird suggests compression via gzip, but that isn't possible through our hosting company, Media Temple.

Following is their response:

David, mod_gzip is replaced by mod_deflate on the Grid server. mod_gzip is not installed. Use this guide to help you enable mod_deflate instead. If your plugin or application relies on mod_gzip it may not work on the Grid:

I need help to activate mod_deflate.

Our staging website is: