Climate control retrofit anyone done?

Hi all i know people have asked this in the past and so far as i can gather people say to stay clear as too much work and will cost too much, well i have a donor car sat outside with all parts i need to complete this, and I believe i possess the skill to do it, just looking for a few pointers or to find out if anyone on Briskoda has indeed done this? 

All the parts I have are from a pre fl and going in a pre fl, i know the full dash will need to be removed from both cars, and the full heater motor unit needs to be removed and replaced, Will any extra wiring be needed?

All help is greatly appreciated i do have a vague how to from a golf which i know will be similar but isnt in great detail.

Dan