TeraFlex JL 4dr: Lift Coil Springs are perfectly engineered for your 4-door JL Jeep Wrangler Unlimited. Our engineers focused on extensive rate tuning and dynamic balance between front and rear and side-to-side load bias to produce Lift Coil Springs that deliver unsurpassed highway handling and off-road performance. Around back, we chose the same tried and true linear rate technology preferred by most automakers including Jeep. Linear rate springs provide the maximum number of active coils under load for consistent performance and predictable handling throughout the full range of suspension travel both on- and off-road. Rear Lift Coil Springs are corner specific. We recommend pairing TeraFlex Lift Coil Springs with Falcon Performance Shocks for superior performance. TeraFlex coil springs and Falcon shock absorbers have been engineered together to improve both compression and rebound for optimal vehicle stability.