One front tire balloon? Thicker front diff fluid.
Both front tires? Thicker center.
Sound like your suspension settings are all wrong. Xt8's don't understeer off power. Maybe you're way too soft, low, or not enough droop in the rear. Wrong tires, too much rear toe in, too little front toe out, not enough rear camber, stiffer rear swaybar.
10/10/3?