Just to clarify things for others.
Yes the 3" (per side) relocation kit made by MOPAR (PART # P4120665AB) or others has been out for many years. But, it only includes the front spring mount.
Nobody (to my knowledge/research) has ever made a kit to mount the rear shackle to the frame (and this is where it gets complicated).
The following items will need to be addressed if relocating the rear springs (2" or greater, per side) inboard;
- Stock shackles can hit the rear valance, shorter shackles eliminate the need to modify the rear valance.
- Existing exhaust system may need to be modified.
- Stronger/thicker and/or custom sway bay may be required.
- Trunk pan may require modifications.
- Of course their needs to be outer frame and wheel well modifications required. Installing this kit without this will not allow for larger tires!
The following pictures are how I modified the rear frame rails.