A few other things to consider are...
- If you want a hard top, it is cheaper to purchase a car that has it included (generally)
- Plastic vs. glass rear window will also determine years you will consider
- Make sure the car has 2 keys/fob - as they are expensive to replace
- Make sure when you lock the car and arm the alarm, there is no horn beeping
- Make sure the headlight lenses aren't burned - if halogen
You should also get a PPI. BTW, I wouldn't think of these cars as an investment as a lot of them are out there.