WDS and Indexing service

hi all,

I would like to use WDS 3.0 through programmatically for searching word document contents. So, I am querying sytemindex with System.Search.Contents as the Where clause.

My questions are:

Does WDS using the "Indexing Service" (which is already available in the system)

What is the difference if I manually configure my target folder with available "Indexing service" and query directly without using WDS SDK

For me its easy to query the WDS component (thru OleDb)  than querying the indexed file directly. So, can I use this technique in production also

Once the Indexing is done for a folder if I add or remove a file inside the folder will it re-index from the first or it will just update the index (I guess it shouldn't take much time to modify the latest changes into the index)

I am confused about IFilter. what is IFilter does it been used in WDS

Thanks!

Regards
Karthikeyan