Most GL owners by now have received the letter from Saturn (as described in other threads).

Has anyone gone to the dealer and had the harness installed and the software updated? If so, please describe any changes to your GL's performance and fuel economy. Also, has anyone had the problem as described, and did it fix it?

Some of us who are pleased with our GL's current mileage (well, at least me) are a little reluctant to have the repair done, as it may change the GL's hybrid performance. That being said, we often go on long (i.e. 16 hour) trips in our GL and worry about the problem described in the campaign...