Well after waiting for the second speaker to turn up because of christmas post i finally got it built up...
The first speaker i chose was just a no go the space you have to play with is tiny so mounting depth and face profile is important.
Not the cheapest speaker but worth every penny for me and the result is supurb.
The kicker 6.75 speaker is a full dual voice call sub and is very shallow with a flat surface when mounted.
Its the speaker of choice when you google it for a zed and although i had to build abox to fit the space the speaker fit is great.
Here the speaker...
Completely flat topped
Very shallow mount at under 3" and the front profile is only 7mm
Four connections to the two voice coils what is good about this sub its also dual 2ohm coils which is what the bmw amp is rated at for load.
My made box with the sub fitted the standard bmw wiring used for connection.
Dropped in the car faces forward and the lid fits perfectly and as seen with the front grill removed the speaker sits behind a beam but sits perfectly forward.
Conclusion... works supurbly lots of bass in fact you can turn it down now !!
Alittle sound proofing to add to stop the odd rattle of the plastic panels but im impressed .... alot well worth the effort