My Doonz are mounted on stock steel rims.
Jake as for rim choice. I would use some kind of bead lock for sand that way you can use low air pressure without worry of blowing a bead. Bead locks will be my choice when its time to upgrade. I have had great experience with bead locks on my quad but have zero with the rex. What I do know is when your out there in the dunes and have no carb cleaner or some other areosol can you can use to reseat a bead. Then you have to pay $30+ bucks to some vendor when you know it only takes 2 min to do yourself than your bead locks will have saved you all that hassle. This is just my opinion and not meant to say non bead locks are bad just what I will be doing when the time comes.
my first trip on the doons tires, i sliced the right rear on a hidden rock. second trip out, i landed hard off a jump and blew a bead on left rear. i am running on the dwt diablos. i would be careful of the offset of the wheels you use. the dwt diablos that came with the set are the wrong offset for the front. the tires rub on the ball joints. A spacer is gonna be required up front with these wheels. other than that, tires are great! there isnt a hill that i cant make up at dumont...
08 LE, DASA 840, Muzzys, CDI, Open Filter Carb setup, VFJ Stage 3, XMF LT w / WER shocks, XMF 2 seat radius cage, XMF bed delete kit and bumpers, Lowrance Baja 540c GPS, HID's, 14" MSA MCX tires on black MSA Diesels, Twisted Stitch Agressors w / XMF seat bases, and a whole bunch of other shit!