do they just replace the useless mfd2 unit like for like, or do you require an intimate knowledge of automotive electrics and panel removal and replacement? 
They are a direct replacement for the MFD2 (and all standard headunits) but as per the pics from 182_blue you need to remove the vents above and the plastic trim around the face first then the headunit is held in place with four torx's screws.
Have a look in the maintenance section at the nokia car kit install, that shows the steps for tking the headunit out.
