Otherwise there are some clues:
- Sport edition: All 6sp manuals; will have a red S on the trunk; Will have staggered 19" wheels; Will have upgraded seats; Will have large silver brake calipers that say INFINITI; Will have a different bumper. I have seen some used G37's listed as a sport that are not a sport. Usually the calipers are the telling sign. There are other differences based on year as the '11 sport comes with the Sonar package too). Also, if the door panels are two-tone then it's a sport edition.
- If there is a "snow" button between the seat heater adjustments you are ensured the car is AWD
- if there is a sensor in the lower grille it will have Tech package
You know, it's easier to look at the bottom of the spec sheets to determine what the packages are. You can find all of the Spec sheets here:
http://infinitig37.com/coupe.html