Jason N--What arrow rest do you use with your FX? I use the Quiktune 1000.
QT 3000
A note about the Leeches not being durable: I can't keep them in my string for any more than about 700 shots. So, since my target doesn't jump the string

I don't put them in until about a week before season. I have not noticed any tuning problems or any changes to the tune after installing any of the SVL products. As far as the good old cat whiskers go.....I tried them years ago when that was the about the only good choice(whiskers, puff balls, etc.) and I haven't used them since the Leeches came about. I never thought they worked very good at all, but I haven't ever shot them on this particular bow. If you go with Leeches I suggest putting them as close to the axles as possible, that's where they've given me the best performance while still greatly reducing noise.