Hi Im new here and was looking for some advice. I have a late 2005 520d Si and I want to put an amp and sub into it. Ive read loads of different posts and nothing is crystal clear so looking for some answers to these questions if possible.

I have speaker to phono wire thing I bought from Halford, I'll cut wires from back speakers and connect them, do I leave speakers disconnected or do I just join the wires onto the existing wires so speakers still work?

Which wire is the correct wire for remote wire from cigarette wire to fuse box? Ive seen the wires and there is are 2 green and white ones, 1 is slightly thicker than the other.

I have read about an amp in the boot and using those wires but I dont think my car has one unless its the silver box just towards the front of the car from the battery in the boot, is this is it which wires do I use?

Any help whatsoever would be appreciated as I would like this done as quickly as possible. Ive put amps and speakers into many cars but always directly into the head unit, never this way so dont want to mess anything up. Thanks and my name is Ged :-)