According to the articles I found online, the cylinder head issue is only estimated to be present in 0.5% of all 3.6L engines on the road, and only comes about under specific conditions of using low quality gas, high temperature, and hard driving. Nevertheless, it sounds like Chrysler made a design change and is replacing the parts under warranty. Nothing to worry about IMO. You can use Google to find issues with any car, just like the Ford EcoBoost issue that came up last week, but seems to be effecting a lot more case than this cylinder head issue.