Don't be afraid to open it up. I was too before I did the OBC hack. Take your time and it will go okay. I installed the controller stalk (without having to remove the steering wheel, i might add.) Get all the instructions you can find on this board, Renn-tech or some of these:
http://www.whiteson.org/boxster/mods/obc/
http://www.whiteson.org/boxster/mods/obc/obc.stalk.pdf
http://www.whiteson.org/boxster/mods/obc/OBC.Wiring.Harness.pdf
http://www.whiteson.org/boxster/mods/obc/OBC.pdf