If you are talking about the rubber sway bar bushings, they are not replaceable. You can replace the entire sway bar for around $300 each. I used H&R from American Muscle, took about 90 minutes each. The H&R bushings are replaceable, and are better material that OE. They did not make the ride harsher imho, but it does corner better.
does anyone know of a site that sells bushing kit for a 2012 3.7L
If you are talking about the rear sway bar bushings, then yes, you can replace just the bushings. I replaced mine with aftermarket bushings that are greaseable. Cost about 120 bucks. I love them. Look here: