I have DNS-323 in 2009. It is good NAS, which is running on 24/7 basis.
DNS-323 has it official BT client, or addon. But I would like to have a more powerful BT client.
Installation is only two steps:
Download two files and put into the root folder on disk1 of DNS-323
fun_plug (installation script)
fun_plug.tgz (source files/packages)
To install BT client, Transmission, I followed the guide here.
I installed the latest version, Transmission 2.76.
After that, I can use web interface to do the downloading.
Transmission provide a lot of features.
So I can easily change the speed, ports, location, or view statistics.
See the screenshots below: