Re: will it fit??
More than likely, yes. The basic engine is the same, but some of the bolt ons are different. I haven't done it, but some of the differences will probably be the intake manifold (truck one is considerably different, and MOPAR magazine says the WK one is better), oil pan (unless truck is a 4WD), ignition coil plugs (unless you use your 05 valve covers/coils....05's and 06's have different coils/plugs), and maybe the oil pump pick up tube (if the truck is not 4WD. There may be other subtle differences, but you should easily be able to swap the affected parts. Good luck and let us know how it goes.
05 LX/RT & 06 WK/GCO, modded similarly, MDS "ON" Light, Vortex Gens, Debadged, DashHawk, BT Catch Can, SRT CAI W/Add Air Inlet, K&N Filter, Sonnax Trans Press Booster, SC Tuner W/Adv Trans Tuning App, DS Tuner, Cust tube headers w/3 in. catback, Bilsteins, SRT frt/rear bumpers, Eibach SRT Lwr Sprgs & Sways, FRI Sidewinder Cam Adv 2*, 6.1 valvetrain, SLP 25% UD Pulley, BBK 90mm TB, SOS Coils/.060 plug gaps. 20 in. SRT Reps.