One more thing to ponder is the trans and rear axle.
There is only enough room for a 727 in a PU without a serious driveshaft problem.
Consider swapping in a late model IRS, so the driveshaft doesn't have to follow the 3rd member. You could probably put a late model trans in then.
Again, if considering air bags, look at what's available before selecting the rear.
Heck, you might try to find a rolled 300 or charger and do a full drivetrain swap. Too bad the front suspension is struts, that will not work!
http://www.airliftperformance.com/applications/domestics/chrysler-300/

http://www.salvageautosauction.com/vehic...illings-Montana