Augwest, I am not sure what is in the devise. iFi normally uses cancellation for noise reduction. I have a DC "Silencer" from iFi, and it does make a small improvement to my Motorola Modem. It does run rather warm.
I saw one picture of the iFi LAN Silencer opened. The case looks to be plastic with no metal shielding, so it may not meet CAT 7 specs.
SOtM makes a CAT 6 and a newer CAT 7 isolator. The CAT 7 has the extra shielding and some minor improvements over the earlier CAT 6 unit. They are both more expensive compared to the iFi Silencer, and require an extra cable because they don't plug in.