If you are looking to buy a Unichip for your BMW then take a look at some of the documents for the Unichip here:

Unichip Documentation and Wiring Diagrams

Information for the Electronic Throttle System

Information for the DISA including wiring pin outs

I am working on a complete Wiring schematic for the turbo conversion using the Unichip to control the DISA, Boost, Throttle Plate etc.