Hi Harry,
thanks for jumping in. I know, that there are still some images, which can be reduced. But since the 4-5 sec waiting time at almost each page call all over the web, it must be something general inheritent, like javascript and css or memory_limit (which is set to 256 in wp-config.php)
Can I only minify js and css with a plugin or can I also put calls together in one file anyhow? (because of the redflag at http requests)