Import/export of entire DT groups to folders

I am unclear how best to use DevonThink as a database/CMS for my scientific  research.  I am currently writing a major grant application, and I have many text documents (RTF, RTFD, Word docs, etc) in a single folder on my hard drive.  If I import this into DEVONthink (DT), it works well to edit the RTF / RFD files the first time.  However, I am unclear as to how I should repeatedly export / import these files so that I can save my work but also edit it later.  If I export the entire directory/group I often end up with multiple copies (usually nested) on my hard drive.  If I export single files or selected sets of files, I end up with multiple copies of those specific files.  That is, DT does not seem to overwrite files with the same name.  In addition, the date/time shown for files I have saved does not seem to be correct all of the time, thus making it difficult to accurately manage the files.
I have read the user forum and the manual extensively but I have seen no clear discussion of this.  
 Specific questions:
    1) How can I export a DT group so that it completely replaces a folder on my hard drive, so that I can back up my DT group on my computer independently of DT, for access to those files with other programs.
    2) Is the time-stamping of file modifications within DT automatically and fully synchronized with the computer data/time?  Can DT be set to do this?

  1. That’s currently not possible (you have to export your contents either to a different folder or delete the old one).

  2. DT handles the modification date on its own (e.g. after modifying a content) and use the system date of course. The creation date on the other hand is either the date of the imported file or the date of the creation.

Finally, version 1.9 will add the synchronize feature and therefore you won’t have to im/export data on your own anymore.