Deploying a search engine should be carefully planned. I would suggest reviewing this section:
Do you require usage of the ContentStore Email Viewer or do you plan on creating stubs and just want basic recall mechanisms available (I.E. archive out a message leaving a stub which is retrievable by end users). The ContentStore Email Viewer requires not only archiving of the messages, but also running content indexing against those message to ingest them into an indexing engine. This can be a resource intensive process, but with this in place you can run 'stubless' archives taking the entire footprint of the message out of Exchange and allowing access through the seperate ContentStore Email Viewer.
You may also want to check your licensing to make sure you are already setup to do Content Indexing.
If you only require basic stub recoveries (and possibly access for end users through the web console), the packages you already have deployed will be sufficient to perform this.