Re: P0430 MIL error with EGR disabled
The EGR system reduces the combustion temperatures, which reduces the occurrence of NOX. It also allows for more timing to be run, because it reduces the incidence knock retard. My Hemi is moderately modified (see signature) and I would never think of disabling the EGR system for the reasons above. Also, if you're in an emissions testing state, the smog nazis will be glad to see you. The other changes to your tune probably made the driveability better. The stock everything (PCM/TCM) settings are crap, IMO, and almost any change would be for the better.
Your P0430 is usually caused by an exhaust leak (I'd check this first), a bad downstream O2 Sensor or a bad catalytic converter. Do you have a way to check/data log all the O2 Sensor Mv readings? That would be the easist way to check their status.
So, I'd look for exhaust leaks first.....especially broken bolts at the exhaust manifolds or leaks at the manifold/Y pipe connection. If all is OK there, I'd try to get the Mv readings off the O2's. If both of the above are good, then take a look at the cat. My $$$ would be on a leak and/or lazy/bad O2 Sensor.
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.