Any idea how they differ from the Sims version? Similar performance?
The Sims version have an additional mounting hole tapped into the center of each unit so that you can add on additional weights, sims modules, etc... Pretty cool in my opinion as it allows you to further customize the balance of your setup. However, they are also pricier than the NV system by about $25.00. I think they sell around $75.00 most places.
I cannot comment on actual performance differences as I have never actually installed a set of the Extreme limbsavers on any bow. I never bought a set for myself and we do not have them down at the shop.
Are you saying you used one of these between the stabilizer and the bow
Yes...and more than one at times. You do need to add a washer though as well as an extra "mounting bolt". I have a few of those laying around from a Cobra wrist strap package I utilize. I will send an extra bolt along with the dampeners if you want to try them as a stabilizer combo.