thought of letting eveybody know a bit more about my install:

my overall requirement:
1. I already had a JBL Sub+Amp, so i wasn't going to buy a new one, was gonna get this fixed into the X5.
2. Fixing my massive box consumed space, so I wanted it to be easily removable so that i could just pull it out when boot capacity was needed.

So i searched around and found a 60amp Vibe connector that allowed push in/pull out connect/disconnect of ground/+12v/signal; made 2 RCA connections for the sound. all this was fitted on the left hand panel, above the nav cd unit.

here are some photos for anybody interested:
1. connection port when the amp+sub are disconnected:


2. amp cables connected to the port:


(Vibe fuse unit is on velcro so easily removable. ground and +12v are 4mm cables, non-standard colours as i already had these from a cousin, they're used for communications eqpt racks and rated upto 90c temperature - much better than amp cables so i just used them although colours aren't right)

3. my x5 boot, when the side panel is closed :



if i need boot space, the whole unit comes off in a minute and goes into my house!

along the way i had major trouble getting noise cancelled, i've learnt a great deal about this subject, so any questions pls ask. happy to help.