The in-tank Carter or Airtech fuel pumps are one of the least costly and best options for adding a primary fuel lift pump to feed the fuel system! Anything that pumps much more than 15 psig discharge pressure is a complete overkill for the demands of the Jeep CRD even if you install a healthy power/torque producing tune...
The Jeep CRD comes factory wired with a relay for the in tank fuel pump; all that has to be added is the wiring from under the back seat to the top of the fuel tank. Many on this forum have done this modification and are very pleased with the results. There are several threads on this forum that cover the install instructions in detail if you decide to go that route....

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Supporting Vendor and Moderator of LOST05 Jeep Liberty CRD Limited 
Ironman Springs/Bilstein/Shocks
Yeti StgIV Hot Tune
Week's BatteryTray
No FCV/EGR
Samcos/ProVent
SunCoast/Transgo
Carter Intank-pmp
2mic.Sec.Fuel Filter
Flowmaster/NO CAT
V6Airbox/noVH
GM11 Bld.fan/HDClutch
IronrockArms/wwdieselMount98 Dodge Cummins 24 Valve