Is this tool the right for me?

Have one Joomla-Page and want to split my 120 MB Datebase in 3 Database but want it to integrate in the one Page under one Domain. Only link the content over the normal menu.

And how runs d´the search? And is there are a bridge to the extension Jreviews?

If you want to split your website into smaller peace, this is possible.
You will probably need to share the users between the website.
Concerning the "article", you could put them in one website to reduce the size of the DB or put a forum into another DB, ....

Concerning JReviews, there is no bridge for this extension.
If you want to share the the content of some extension, see the list of extension and the one that can be shared.
www.jms2win.com/en/list-of-extensions?vi...id=269&Itemid=53
If you share the content of some extension, the MySQL table are shared (not duplicated). So you will not save disk space.

Concerning the Search, with the "Multisites Search" plugin, it is possible to merge the results from different websites. This plugin allow searching in the articles, categories and section. Not in the content of the other extensions.

JReview is not an extension that can be share and you may have limitation concerning its configuration.
As this is an extension that is encrypted with IonCube, any problem of compatibililty must be reported to JReviews author as their code is encrypted.

And how it runs with the menu?

can I use the Joomal-SEF features and linkung directly to the Content-category?

Have a news site with this URL domain.de/news/2010/alias/
But want the news now integrate in an news database, because it is to big. If I use the JMS Multi Site Component can I build up this menu?