Turbos are the big item, seems to affect earlier years rather than later but all the 4.0t cars can develop the problem if they hadn't had the new oil screen and fittings applied. I saw a couple cars on CarFax that listed the turbos having been replaced, That would give me a little peace of mind.
In the end the if the turbos fail it's not super catastrophic. You can buy upgraded turbos for less than 2k and the install is a DIY.
Other than that oil separators, turbo coolant o-rings, and motor mounts are the main issues, with turbos and thermostats being less common.