After you are done buying by the piece, you might want to ask how much for the whole lift. Since there's probably more pieces for the front than the rear on a xj, you may find it costs the same or just a little more to buy the whole thing. Then you can sell the rear springs and other parts to try and recoup the extra costs.
Here's what the RE 5.5 comes with:
Sway Bar Relocation Brackets 1
Support Braces For RE9900 1
Sway Bar Disconnects Adapter Bracket XJ-ZJ 1
Sway bar Disconnects Set With 6" Centers Tube 1
BRAKE LINES SS FT XJ/MJ/ZJ/C 1
Control Arm SF2 Lower Fixed 1
Extra H.D. Track Bar XJ/ZJ 1
Control Arm SR2 Upper Ft Fix 1
H.D. Track Bar Bracket XJ/ZJ 1
3" Front Bumpstop 1
Coil Springs ZJ 4.5" Front 1
XJ Control Arm Drop Brackets 1
4.5" Extreme Duty XJ Rear Spring 2
Brake Line SS Rear XJ/ZJ 1
U-Bolts YJ Dana 35 Rear 1
Shackle XJ Rear 1.25" Lift 1
T-Case Lowering Kit XJ/ZJ 1
Since there's 17 items and you probably only don't want the last 5 on the list, it might be better to bite the bullet and just buy the whole thing.
Unless you just need the springs, then just call most any parts joint and just buy the springs.
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