I have the standard STS system on my Allegiance and I to was looking at the double. I have a few concerns about it though. First, how much better can it really be? How are two STS stoppers within a couple inches of each other really going to help? Maybe a little faster vibration reduction for the string but thats about it. My second concern was setting the system up. To get it to actually perform its best you would have to set both stoppers at the exact same distance from the string, otherwise one is pretty much not being used. My final concern is with weight. I know that the STS system doesn't feel heavy but if you take one off a bow and put it back on you can feel a noticeable differance. I would think that this new double STS system would probablly be around 135% heavier which just doesn't seem worth it.