Things to look for, well there are a few
1, Ensure you get full service history
2,Get as much warrenty as poss as these things are not cheap to fix.
3,Get the Nav model as you will regret getting one without.I wouldnt say go fully loaded as some of the options you get are not needed and can be more of a headache than their worth.
4, Dont let your money burn holes in your pocket as there are plenty out there to choose from.

I'm sure other members could add a load more things but its a start.
Cheers