Do you have control over the site or someone who works on it for you?
AddOutputFilterByType DEFLATE text/plain
AddOutputFilterByType DEFLATE text/html
AddOutputFilterByType DEFLATE application/xhtml+xml
AddOutputFilterByType DEFLATE application/xml
AddOutputFilterByType DEFLATE text/xml
AddOutputFilterByType DEFLATE text/css
It’s trivial to implement and there are no risks associated with it.
There are two other changes that will have a HUGE impact but they are a little more involved:
2 - You need to add expires headers to your static content so the browser will cache the files (all of the yellow highlighted requests in the repeat view can be completely eliminated). This is a little trickier because you need to make sure to change the file names any time you do an update but the win is well worth it
Don’t do anything else until you have at least addressed these 3 things and then you can take another look. The next biggest win will be in combining a lot of the page graphics into an image sprite which will eliminate a whole bunch of the individual requests for images.
Ultimately you should be able to get the page load time reduced by ~75% with just a little bit of work.