Just got some new tires for my 2008 FJ and the guy at the shop mention that the reason my tires are wearing on the inside of the tire is due to the rear shock need to be replaced. So been shopping around and was wondering if I need to replace my rear springs too if I'm going to replace my rear shocks. So notice that Toyota makes rear springs for a 2X4 spring and a 4X4 spring. So I decided to call one of the Toyota dealerships to see what is the difference between the 2X4 and the 4X4 spring. Is there is a difference in height between the 2 springs or is the 4X4 spring has a larger diameter in spring. Well he could not tell me the difference just that they were different in price. So I'm asking if there a difference in the height between the 4X2 and 4X4 spring and will it work on a base model FJ. Oh by the way my FJ is a 2X4 and was thinking of putting the 4X4 spring along w/ the TRD struts, but if there is a difference in the height of the springs then I might want to stay w/ the 2X4 spring if I need to replace my rear springs too. Thank you.