both actually , I ordered 4 1/4 backspace when I got the rims but they are too close to the springs , I went with the Nitto 555R in 275/60/15 because I thought the 11 inch section would clear but I`m going to have to space the rims as well or breakdown and swap to the offset shackle package , as I said above the X is going to be way off because the center of wheel to center of wheel front to back on the passenger side is 106 7/8 when it should be 108 like the drivers side or at least 107 1/2 when you figue in the 1/2 inch of thrust offset that was built in according to what I am reading , I`m going to fix that with 1/2 of spacers made form scrap steel then I`m going to add 5/16 spacers to the wheels themselves which should give me more that 1/2 between the tire and the spring .Luckily 2nd gen barracudas have plenty of room in the wheel well to push the tires outward with out getting into the wheel lip .
