Hey I'm new to the site and bought a xr6t last week, it has been custom tuned and was wondering if taking battery out will reset any if this. Very dumb question I know but I have always had old cars so it's all new to me hah. Gotta start somewhere. Cheers:)

All you will lose is radio settings and the gearbox (if auto) settings will reset to default.

You may get a "Code Error" on the radio but it will reset once you start it and then turn it off again. The once the ecu is flashed it stays flashed until you re flsh it with another tune. Did the car come with a flash unit or do you know who tuned it? If you don't know, find out. Can be useful later on.