Stupidly simple. It takes 5 minutes once you have the CC unit out.
3 screws to remove front panel, I think about six screws to separate the circuit board from the front panel, twist the metal LCD frame tabs straight to remove it from the board, then pull it free. Swap panels, then put it back together.
No soldering required. You'll need a philips head screwdriver and a pair of pliers (standard or needle nose).
Some pictures here:
http://www.rennsportkc.com/996boxster-climate-control-display/