The 2015 EBS versions have different clutches on them. Engine braking is very valuable for some riders, and not necessary for others. It can be rider preference. The EBS versions were not calibrated as well from the factory, and clutching performance can be improved upon for stock or oversized tires. There are also adjustments to help with power losses from higher elevations. Accurate clutch calibration is important to belt life, performance, and backshifting in load conditions.
The clutch kit for this model not only has the adjustable flyweights and springs, but it also has a new helix included. It is actually 2 helixes !. The solid billet helix has 2 different sets of ramp curves machined in it. The helix ramp used for your application depends on tires size and application. Everything is in the instruction manual in the "set up guide". It shows you how to set it for your tires and application....as well as how to change it if you change the tires, etc in the future.
*There are some model variations for EBS application. If you are unsure if your 900 RZR version has EBS clutches, your Polaris dealer can run your serial number to confirm.