Richard, read the forums, there's lots of info there. In my experience (with four SDFB) all components "react" to the SDFB in a consistent manner. A clearer sound, a bit more dynamics. The Sluggos are finer tuning devices within the improved sound, and I've tried four or five different ones and I find the Graphene to give the best resultes for me and my system. It really is a "personal choice" type of thing.

In my case I would say that if you have a regenerator or some sort of power treatment that may be the component that would benefit most. In my system I no longer have one (but I did and the SDFB made a bit impact, and I now have one before the regenerator in my audio/visual system, and that's the only SDFB in that system). In my system now I would rate the improvement with the SDFB to be biggest with the amplifier, then the DAC and then the ZROCK3. That was the order I installed them, the ZROCK3 last, but it was an incremental improvement with each. If you are going to add one I'd try the power treatment and the amp and see which sounds best. It is probably system dependent.