Aucutally, Lizzy - he's got an 04 so its different.
You'll want an EVSII (Same thing I installed)
This from MyDodgeParts.com.
82207139
$227.00 $227.00
$151.25 EVS II Security System w/Sentry Key and Interior Theft Senso
2002-2004 Liberty For vehicles w/remote keyless entry system, complete kit includespanic feature, interior theft sensor, Sentry Key immobilizer andelectronically coded ignition keys, no wiring needed.
You can do the shock sensor yourself, but the dealer needs to activate the alarm in the BCM. Don't attach this yourself, or you'll have to tow the jeep to the dealer.
-Blu