I found the ADSL Nation filtered faceplate very worthwhile, although I did have an existing problem that I didn't ever find the cause of, but which the ADSL nation faceplate circumvented.
After my ADSL was switched on, I could hear it as a hiss on the line, and speech quality went down, despite trying different filters on the telephone. Previously line quality for speech had been excellent.
I fitted an ADSL filtered faceplate, and this problem was resolved - speech quality excellent again.
It also gained me additional throughput and slight reduction in attenuation.
So, in every regard, I was very pleased
Regards to wiring, I'm sure someone else here will be able to give you more detailed instructions, but basically :
phone line into house goes to the A & B terminals.
Your extension sockets are then wired to the 2 3 and 5 terminals.
This has the effect of removing ADSL signals from all extension sockets (so you no longer need microfilters on each extension socket that's in use), and eliminating (or significantly reducing) interference from those sockets getting back to your ADSL signal.
If you've currently got wires going to terminals 2 3 and 5, then you've got the ring wire connected. You don't need this, and it can cause problems with ADSL. Disconnect the wire on terminal 3. You only need 2 and 5. Then resynch your modem. Did the throughput increase?
See here for more details
http://www.kitz.co.uk/adsl/socket.htmIan