Before I put the body lift on I had trimmed a little bit of the inner fender (nor cal fender mod) to clear the negative offset wheels and 32 inch tires. But im not sure I would have needed to trim the fenders at all to clear the biggers tires with the body lift, they clear nicely.
Just finished the Zone 1.5 body lift and got new treads. I am happy with how it turned out.
2014 Silverado, 2.5 Rough Country Level Kit, 1.5 Zone Body Lift, 20x9 -12 offset XD Rockstar 2s, 305/55r20 Nitto Trail Grapplers.
Thanks to several on this forum for their help and pictures!