I've yet to have problems of any sort with the FIM cable. While I don't live in an "RF rich" area, others that I know do, and haven't experienced ANY problem. The dealer that you mention may be trying to persuade you into a purchase with more mark-up, or more profit. But problems with FIM cables, no way, I agree entirely with Mikeam. Hope this helps.
FIM Gold Power Cords Problems?
I have spoken with some one who asserts that while FIM is a good PC, it may have problems in RF rich areas, may have problems when used with other FIM PCs in same system (due to coating) and may be so stiff that they are a real hassle to use. Comments would be appreciated.