Shocks "dying" at 28K miles is in my experience unknown. (My experience over the years is no shock trouble in 28K miles to 317K miles. Except for my first car with "struts" which needed some attention I have not had one bad shock.)I've noticed in the last 2K miles that my GT Plus Perf Pkg just isn't as stable as it was, seems to be bouncing where it didn't before and overall just seems "unsettled". Prior to this, it was very confidence inspiring and stable, already pulling 1.15 g's cornering. It sure feels like the Bilsteins are dying. Anyone else had this problem? So far honestly I've had a lot of little "quality problems" and I'm starting to worry about what else is going to take a dump on me.
What are the odds Dodge will replace the shocks under warranty if they aren't actively leaking, etc.?
If they don't I'm thinking about Konis - any thoughts on them in the Challenger?
While rare more common is a shock will develop a leak.
If you suspect the shocks are bad have some one drive your car while you follow in another car -- as a passenger so you can observe/film your car -- and see if you can spot the signs of bad shocks. The car porpoising after encountering a dip in the road. Or a wheel/tire going up and and down like the tire is running over rail road ties.
In some cases a bad shock can be diagnosed by a bounce test. This involves pushing down on the corner of the car then letting up and repeating this to get that corner of the car going up and down. Then stop. The car's motion should stop almost immediately. If it does not this can be a sign of a bad shock.
If you can capture the symptoms of a bad shock or shocks on camera or can demonstrate with a bounce test a shock is not up to par you stand a chance of getting the shock or shocks replaced under warranty.
As another poster noted the car comes with Bilstein shocks. One of the top if not the top brand of shock. If one or more shocks are bad I'd get them replaced under warranty with OE hardware.
While Koni shocks are good shocks -- used to run then on my motorcycles -- unless the factory shocks even in good working condition proved inadequate -- which is highly unlikely or we'd be flooded with posts of people with the same complaint as you have -- I can't see just switching shocks because you think the factory shocks are "dying" at 28K miles.