[Plugin: W3 Total Cache] Still having load time issues

Hello,
I’ve noticed lately that my site seems to be having load delays despite using the plugin with enhanced disk caching, minify and database caching turned on. Especially my homepage loads pretty slow sometimes. According to web page speed report I have issues with css, javascript, images, etc. Here’s a typical report about one of my pages:
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* TOTAL_HTML – Congratulations, the total number of HTML files on this page (including the main HTML file) is 1 which most browsers can multithread. Minimizing HTTP requests is key for web site optimization.

* TOTAL_OBJECTS – Warning! The total number of objects on this page is 52 which by their number will dominate web page delay. Consider reducing this to a more reasonable number. Above 20 objects per page the overhead from dealing with the actual objects (description time and wait time) accounts for more than 80% of whole page latency. See Figure II-3: Relative distribution of latency components showing that object overhead dominates web page latency in Website Optimization Secrets for more details on how object overhead dominates web page latency. Combine, refine, and optimize your external objects. Replace graphic rollovers with CSS rollovers to speed display and minimize HTTP requests. Consider using CSS sprites to help consolidate decorative images. Using CSS techniques such as colored backgrounds, borders, or spacing instead of graphic techniques can reduce HTTP requests. Replace graphic text headers with CSS text headers to further reduce HTTP requests. Finally, consider optimizing parallel downloads by using different hostnames or a CDN to reduce object overhead.

* TOTAL_IMAGES – Warning! The total number of images on this page is 39 , consider reducing this to a more reasonable number. Recommend combining, replacing, and optimizing your graphics. Replace graphic rollover menus with CSS rollover menus to speed display and minimize HTTP requests. Consider using CSS sprites to help consolidate decorative images. Use CSS techniques such as colored backgrounds, borders, or spacing instead of graphic techniques to reduce HTTP requests. Replace graphic text headers with CSS text headers to further reduce HTTP requests. Finally, consider optimizing parallel downloads by using different hostnames to reduce object overhead.

* TOTAL_CSS – Warning! The total number of external CSS files on this page is 6 , consider reducing this to one or two external files. Combine, refine, and optimize your external CSS files. Ideally you should have one (or even embed CSS for high-traffic pages) on your pages. You can optimize CSS files using shorthand properties, grouping, and then minify and GZIP compress them to reduce their footprint. Remember to place CSS files in the HEAD and JavaScript files at the end of the BODY to enable progressive display.

* TOTAL_SIZE – Warning! The total size of this page is 466139 bytes, which will load in 103.30 seconds on a 56Kbps modem. Consider reducing total page size to less than 100K to achieve sub 20 second response times on 56K connections. Pages over 100K exceed most attention thresholds at 56Kbps, even with feedback. Consider optimizing your site with Website Optimization Secrets, Speed Up Your Site or contacting us about our optimization services.

* TOTAL_SCRIPT – Warning! The total number of external script files on this page is 6 , consider reducing this to a more reasonable number. Combine, refactor, and minify to optimize your JavaScript files. Ideally you should have one (or even embed scripts for high-traffic pages) on your pages. Consider suturing JavaScript files together at the server to minimize HTTP requests. Placing external JavaScript files at the bottom of your BODY, and CSS files in the HEAD enables progressive display in XHTML web pages.

* HTML_SIZE – Congratulations, the total size of this HTML file is 15541 bytes, which less than 50K. Assuming that you specify the HEIGHT and WIDTH of your images, this size allows your HTML to display content in under 10 seconds, the average time users are willing to wait for a page to display without feedback.

* IMAGES_SIZE – Warning! The total size of your images is 340842 bytes, which is over 100K. Consider switch graphic formats to achive smaller file sizes (from JPEG to PNG for example). Finally, substitute CSS techniques for graphics techniques to create colored borders, backgrounds, and spacing.

* SCRIPT_SIZE – Warning! The total size of external your scripts is 90544 bytes, which is over 20K. Consider optimizing your JavaScript for size, combining them, and using HTTP compression where appropriate for any scripts placed in the HEAD of your documents. You can substitute CSS menus for JavaScript-based menus to minimize or even eliminate the use of JavaScript.

* CSS_SIZE – Caution. The total size of your external CSS is 19212 bytes, which is above 8K and less than 20K. For external files, ideally keep them less than 1160 bytes to fit within one higher-speed TCP-IP packet (or an approximate multiple thereof). Consider optimizing your CSS and eliminating features to reduce this to a more reasonable size.

* MULTIM_SIZE – Congratulations, the total size of all your external multimedia files is 0 bytes, which is less than 10K.
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What especially troubles me that it tells me to minify and compress – I thought that the minify option in w3 already takes care of that? Does that mean I can and should compress/minify even further? Do you have any advice how I can do that? Maybe gzip compression? Are there any plugins for compression that are compatible with w3?

Also, how come I get this report even the second and third time of analyzing the same page? I thought w3 cache should do its magic at least the second time the page loads.

I really want to optimize my site so I greatly value anyones input. Thanks!

p.s: My images need to remain self-hosted.