Fitting bluetooth car kit

Stereo power plug/lead could be an idea. Most of the audi head units even have a little sticker on them telling you what the pinouts are. I'd check the current draw of the kit first though. Don't want to overload things.

Hi Adam,

Depending on the year of your S3, you may or may not have a switched live running to your head unit. If so you can tap into that, otherwise as later S3's used the CAN BUS to switch on/off with ignition, you will need to run a feed from the fuse box. Very easy see here

The control unit can be comfortably hidden behind the glove box.

also with the glovebox out, you should see lots of good earthing points!

I took the permanent live for my bluetooth kit from the back of the cigarette lighter.