Hi mate.

The diffs can be a weak spot for some of them. also electrical problems can arise in certain cars,
Make sure the air suspension works fine, test ALL electrics

Finally, ask what recalls it may have had. also what warrenty work has been carried out and by what dealer! some dealers are good, others are bad. the level of warrenty work can give an idea to the condition of the car. generally it could be software updates that solve problems, other times replacement parts.

Other than that, enjoy the height of 4x4 luxury/capability.

ps, if using off road. switch DSC OFF!!!!!!!!!!! Helps alot!