Most hard-core Jeepers know about the Black Diamond XCL (Xtreme Coil Link), a Warn-engineered kit that redefined rockcrawling in 1996. Black Diamond created this production coil-conversion kitso that YJ and later-model CJ owners (and inexperienced shops) didn't have to fumble through a custom longer-travel suspension project.
Superlift acquired Black Diamond and spent the past five years R&D-ing a successor to the XCL (which is still available). Two priorities emerged: simplifying installation and creating a kit that was more street and trail friendly. Controlling weight transfer-especially at pavement speeds-is what sets the X2 apart
Features
The X2 kit differs from XCL in four main areas. The X2's long-arm front suspension is four-link (compared to XCL's three-link), and the rear is leaf-spring-over-axle (SOA) as opposed to the previous triangulated four-link with coilovers.
For YJ applications, the X2 kit includes progressive-rate front coilovers and axle bracketry for the front link arms. Single-spring coilovers (optional for TJ applications) got the nod because of quieter operation than dual-coil designs. The coils are coupled to 10-inch-travel monotube gas shocks with remote reservoirs.
To address the factory stability issues under torque load, both YJ and TJ systems use rear SOA leaves that are designed specifically for the kit. The packs have nine thin, shot-peened leaves with tapered ends, antifriction pads, military-wrap main leaves with OE-type rubber bushings and bolt-type spring clips. Their U-bolt plates have integral bumpstop extensions, and boomerang-style shackles clear the bumper during suspension travel. Black Diamond SS rear monotube shocks by Bilstein provide damping and enough length to accommodate additional suspension travel.
Up front, the X2 uses Superlift Rockrunner link arms, which have threaded ends that won't bind, unlike Heim-style joints. The arms are made from 0.188-inch-wall DOM tubing (1.5-inch OD uppers, 2.0-inch OD lowers), and they're contoured to allow full lock-to-lock steering and maximum ground clearance. The longer the arm, the less the operating angles during suspension cycling, so more movement is possible before the arms bind within their mounts.
These extended arms attach to the frame at the X2's skidpan assembly. Two side rails serve as rear mounts for the link arms. The rails also support the 3/16-inch-thick inner pan, which functions as a transmission crossmember.
Steering correction is also addressed. The kit includes a dropped pitman arm, an adjustable track bar with bracket, and a lateral brace. These components are compatible with the OE under-knuckle tie-rod or a "flipped" high-steer arrangement.
The existing suspension and axles must be removed. A reciprocating saw amputated the exhaust system, which needs to be rerouted around the Black Diamond long-arms and over the skidpan. This YJ already has a required slip-yoke eliminator kit on its NP231J transfer case. | 
On YJ applications, the rear pair of the front spring hangers and track-bar frame mount must be removed. Also, the stock shock towers need to be cut flush with the frame to clear the kit's coilover hoops. The e-brake tensioner bracket must also be trimmed. | 
The system's skidpan side rails catch some of the factory holes. Additional frame-hole locations are marked with the correct-size transfer punch, then a stepped bit is used for drilling. Each hole houses a crush sleeve to reinforce the Jeep's frame. |
The inner pan serves as a transmission crossmember. It's contoured for easy access to serviceable parts and fill/drain plugs. | 
After the shock towers are trimmed, the kit's YJ coilover hoops are installed. Two factory holes are used, and a third is drilled for each rear leg. All new holes take sleeves since these hoops support the vehicle's weight. Bumpstop lowering brackets are already installed. | 
The coilover hoops accommodate brackets for a lateral brace on the new track-bar bracket, which adds rigidity. The driver-side hoop assembly also contains the upper attachment point for the track bar. |