Re: SRT-8 Driveline swap
While the parts swap is easily possible, the sticking point will be (at a minimum) the the PCM/TCM. On your 05 with the 545RFE transmission, the PCM/TCM is combined in one unit. The NAG1 has a TCM that is separate from the PCM and is located on the driver's side, under the dash. This would mean you'd also need the SRT powertrain wiring harness. IMO, doing this kind of swap is both a waste of time and money, and you'll more than likely encounter problems with getting everything to play well together. If you had a wrecked SRT laying around, that may be a different story. I think you'd be better off in the long run by selling your 05 and picking up an 06 or later SRT. Then you'd have the best of everything.
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.