Any Mathews dealer can get the strings for you, they are still and will always be stocked and made by Mathews.
Although Mathews strings are awesome and they revoloinized the string market with Z twist, string amterial and other inovations IMHO their servings on the strings still suck, which bring many issues with serving separation or slipping, especially on the Xtreme point of the cam roll over.
For close to same cost for stock strings you also have a choice to have custom built strings made exclusively for the Z-Max..
IMHO Worlds Best Strings really are the best, they have totally eliminated the serving seperation issues, and the strings are custom made so precise its actually scary how close the strings are to making the bow in manufacturer Spec tune right out of the package.
I personally swap out stock strings on my new bows right out of the box with Worlds Best Strings..you can have custom colors, made and shipped to your door usually within a week...
http://worldsbeststrings.com/
Give Allan a call, you will not be dissapointed..
Neil