Yes they are the same diameter coil. Only differance is the lenth or hieght of the coil. Also the "spring rate". Yes OME makes 2.5'' lifts for the TJ is 3 different duty or "spring rate" levels. The reason I use ZJ coils in the front is due to the spring rate of the coil. It helps with all the added weight on the front of my jeep. "IE" winch, heavy bumpers and aftermarket steel fenders not put on yet. If you need Guidence on what spring rate or coils you need for your needs,,, Give Dirk a call at DPGoffroad= Tell him your plan or want/needs for your jeep and he will set you up with the coils you need to preform or ride well at your request.