97.5 GS 142,000 miles. Still runs good. I would like to get a scan tool to keep an eye on her. I would like to get one that allows me to make changes such as timing, shift poits etc...Any suggestions? Since I live in Vegas I would also like to be able to check engine and trans temp..

Your typical odb-ii scanner cannot be used to make any changes to the PCM module programming and flash the revised program in. That function is not provided for the cost. You'll need a Powertuner or a re-programmed PCM from either DHP, Intense or ZZP.