Don't worry about the solid mounts giving the car a harsh ride. I installed a set in my wagon and the harshness was no worse than a '72 - older B-body. Where I noticed a HUGE difference was on bumpy/washboard roads. With the old rubber isolators, my wagon felt loose, and would dart about. With the solid mounts, on all but the worst washboard, the car now feels more solid and holds a line.
If your Charger is a small block, you probably won't feel as drastic a difference as you would in a factory big block car IMHO.