I've been using the PageSpeed part of firebug on my site and it seems the two issues holding me back from getting over 80 rating are

a) enable compression

b) combine external js/css

I have private downloads on my site - it's mission critical and there's no way around that. What are my best options, either within or outside of drupal for tackling these problems. I have 23 style sheets being loaded into every page, 70% of which are not being used.

It seems half of the tools available to users on the Performance page in Admin are not available to those using private downloads.

Regards

Neil