Last I knew, the Magnums came base with the 2.7 not the Charger and 300. Their base is the 3.5L. I got that right from DC's websites. I did read and also hear that the fleet and rental Chargers came with a 2.7L.
*Edit: I stand corrected the base engine in the 300 is the 2.7 not 3.5. But everything I've looked at for the Charger indicates the base is 3.5L.
6) Modified the PCV system
the modded pcv started with at least the 2001 model as mine has the heat exchanger on mine. I know the '99 didn't because a member on here a ways back retro fitted one on his '99 Corde. The purpose of it was to keep the blowby gases nice and hot so water vapor wouldn't condense out and end up contaminating the oil. As far as the other supposed improvements, I'm not sure. I haven't read anything official and probably won't since DC didn't want to admit to a sludge problem in the first place. How are they gonna make public the improvements to an engine to correct problems that didn't exist in the first place?? It makes for an interesting press release.
One thing I have read that might be tied to 5) Changed bearing materials for the rods and crank, is that the 2.7 in the Sebring/Stratus calls for 5W-20 not 5W-30. If in fact 1) Reduced the internal operating temperature by reducing the temperature of coolant. I've read that the coolant temp has been reduced by around 30 degrees is actually true then that might also be why the change from 5W-30 to 5W-20. I mean think about it, why would you put a thinner oil in a hot running motor? One speculated reason for the 5W-30 to 5W-20 switch was to satisfy the CAFE standards and that lower viscocity shows a very marginal increase in fuel economy.
3) Redesigned the main timing chain tensioner, is something that was done a while back, and maybe by the 2001 model year. I have a good rebuild site bookmarked in my PM's that tells of some of the differences with the 2.7.
I will post it later when I find it. Allpar is another good site for DC stuff.