No, you do not need coilovers to run wide wheels. The coilovers outside of the suspension benefits allow you to tuck the wheel/tires closer to the hub. I have heard about stresses on the bearings and hub with high negative offsets, but I have never witness a failure on a Z. I have seen these guys, that can not decide if they are lowriding or not with these wire wheels sticking way out. I know that is accident waiting to happen !!! Hopefully, ZR8ED can chime in, I think he is running 17 x 11 with 315/35-17 without coilovers on the rear. I am not going that wide in the front, so those who have can comment on that. I am looking at 235, 245 and 255 40 17 up front. Quick question, have you check to see if they will make the wheels in 4-lug bolt pattern?