They are basically the same, I am running RE TJ 4.5" coils up front and are 1" taller than my old RE XJ 3.5" coils I believe the spring rate is the same also.
Fitted them front and rear but just compress them fully along with the stock shock to make sure they go as short. From memory they were longer but just glued in a hockey puck on the coil seat to make up for the difference.