[M3amigos]

I'm in the process of installing an aftermarket sub amp and am trying to source a switched 12v signal for the amp remote. I have an 08 e93, no nav and no eps. In past cars, I've successfully wired into the cigarette lighter, is there any reason why this shouldn't be done in the M?

So before the search Nazis start flaming, I've read all about pin 13 and the LC2i, but I am unsure if this signal can be routed directly to an amp. What voltage is this signal and is it ignition switched?

Ideally I'd like to tap something in the trunk, any suggestions. Would it be advisable to add a relay in line?

Thanks.