4 clips? There are 2 clips that you have to move inwards, (look in the housing where the wiring harness connects) And then you move the top board at a 30 to 45 degree angle, and slightly twist it from side to side will pulling it also.
Did you look at the instructions on Bruno's site?
http://www.bmwe34.net/e34main/upgrade/chip.htm
Here are some other instructions that may help:
http://www.bmwe34m5.com/faqs/?theme=...nt_id_select=3
(installing an EAT chip in an M5, but it's the same dual board system you have)
Mark