I'm running 20x12 -44 offset with 35x12.50r20 on an 03 CC LB7 with just a leveling kit. custom fender walls and a lot of trimming but it will fit. if you want to go conservative- do 20x10 with a smaller offset and do either 305/55r20 tires or 33x12.50r20. you will still need to do a little trimming on the front bumper but nothing major or noticeable. offset means how close the center of the wheel is to the inside of the truck. the lower the offset the bigger the "lip". my -44 offset have about an 8 inch lip.