Two things:
1) A LOT of folks on here have said the gibson doesn't sound too good on the Hemi... make sure you've heard one and like it before you spend the $$$.

2) Depending on your year, there may be one or two resonators. One before the muffler, and one in the tailpipe just behind the rear axle. It "tunes" the sound of the exhaust to cut out some of the annoying frequency in the cab, or "resonance," which is where it gets its name.