I was in the same boat 2 years ago , every thing the guys have said above, also to check and make sure all recalls are done, on car and check the oil cooler house has been replaced with all metal one, also make the car comes with 2 fobs.
i went with the ZR6 as I liked the leather seats over cloth, I wanted the duel climate control air and push button start ,
it comes to down service history , good luck and let know what you get 🙂