This may be a stupid question but I looked everywhere and it's driving me mental: above the back seats there is a little box attached to the ceiling, with small grill facing the front. It's right below the antenna. I can't think of what that box is for, any ideas? It's a 2004 Cooper S.

 

It's the housing for the sensor should your MINI have the OEM alarm system. pre wired but an empty void if not, I'm planning a few mods that might make use of it.

 

Aha, so in my case it's an empty void then! Thanks, would have never figured that out. Let me know what type of cool mods you're planning to do with it (does it have 12V feed in there?)

 

It's also standard on most BMWs. My friend was surprised to see that his 3 series has the same part on his headliner as my MINI.

 

You work for the Department of Redundancy Department don't you.