Thanks for the reply it will be interesting to read your review on the above kit after you have it installed.
With the spacer I think E90/91 is a bit more forgiving on the front speaker mounting depth whereas the E92 has a maximum 44mm mounting depth (somebody correct me if I am wrong). I may try to find some abs plastic sheeting that I had left over from another project that is 2/3mm in thickness but very strong.
I am going to be taking my door card off again to dynamat so I will take some measurements as to whether I can fit 5" comps which has a shallow mounting depth.
Are you going to be mounting the amp and cleansweep in the hole in the boot under the carpet?