Also, something I've seen implemented elsewhere (with various levels of success!) is an auto-clean up feature:
1) check and move files that are part of the PAR2 set to a destination subfolder (named after the PAR2 file or some other configurable name), then perform the unRAR if necessary
2) move any extra "wanted" files from the source folder that were not included in the PAR2 set (from a wildcard list such as "*.nfo, *.jpg" etc.) to the new destination subfolder
3) delete the source download folder if it's either empty or only includes "unwanted" files from a wildcard list (such as *.nzb, *.m3u, etc.)
4) optionally delete "unwanted" files from the destination folder, even if they were part of the PAR2 set or part of the RAR set
The closest I've seen to this feature is Newsleecher with PAR Buddy running along with it, but it has a few problems. Newsleecher has a nasty habit of deleting downloads under certain circumstances

