You cant go wrong with either, the thing about looking for a tire prep line/ tire guy is who is able to give you the best support for your situation, not just with preps, but tire and chassis info as well! I highly reccomend Kevin Bishop with Venom, he has been on the karting scene for a long time worked with chassis and tires along some of the best in the buisness. Contact them and you decide who would be best for your application.
Nick Welch
Wicked Cuts