I fitted it on a 2003 about 5 years ago and it needed a new harness from the ULF and bluetooth antennae at the rear and another harness right through to microphone in the steering column at the front and lots of other bits
The main harness is no longer available from the aftermarket company that used to make them, nor the BMW central harness 61120154335
These are the parts I used:
32 31 6 765 395 Trim Panel Upper Part £49.10
51 47 7 033 004 2 pieces Screw £0.45
07 11 9 902 932 5 pieces Hex bolt £0.26
07 11 9 904 019 3 pieces Hex Nut £0.38
61 12 0 154 335 Retrofit Wiring Harness* £123.54
61 13 1 372 033 5 pieces Body Nut £0.80
61 13 9 410 951 2 pieces Protective Strip £1.06
84 10 6 922 719 Bracket Transmitter-Receiver* £11.29
84 31 6 937 391 Hands Free Telephone Microphone* £20.00
51 46 7 066 181 Trim piece grey (flap)* £67.50