I have a 08 Honda Civic. I'm thinking about buying a scangauge (http://www.scangauge.com) for monitoring my MPG. I have 2 questions-
1) This device attaches to the OBDII port. Where is that located? Am I going to void my warranty if I install this?
2) Is this device any good? I noticed that there was a group purchased planned for September 2007.

Thanks

 

The port is located right by your right knee under the dash, and no it won't void your warranty. It works very well for showing trends in mileage, but it's accuracy varies with temperature (or so the reviews say). If you want to help yourself get the best mileage you can, the scanguage will help. If you are keeping a logbook of actual mileage then the oldmath method works best. I am planning on getting one shortly.