Most of the differences are just cosmetic. The Xtrema 2 has a larger trigger guard and trigger area to accomodate gloved fingers. Safety is larger also I believe. It features the Aqua coat weather treating, which prevents rust (and does a hell of a job at it too). I don't know for sure if the first Xtrema used the longer Optima chokes or not, but the Xtrema 2 does. It also has the option of the Kick-Off recoil reducer. Functionally they are damn near identical.