I briefly looked around under the dash with a flashlight and I can't see any obvious signs of something wired in. Checked the fusebox as well and didn't see anything.
I haven't had a chance to disconnect the battery yet.
I do have a little button thing on the passenger side of the dashboard. Any idea what this is? Not sure if it's factory or added.
Also do all the cars have an alarm system or anything? I know when I lock or unlock the car a security icon on the dash lights up.