ok I can get you wiring diagrams for everything, since both are similar era you shouldn't have as much trouble with coding though may still need some work done if the ecu isnt happy with your interior modules. how far do you want to go with it? add the mk5 clocks etc as well or literally just engine? probably a good plan to start a new thread for it, might get more hits
So as bad as it sounds. Just get It in and running. Then I'd look to add aftermarket clocks for track days etc.
you'll probably find the original dash works fine, just not sure if the immoiliser etc will code and if it'll be happy with the various internal modules. so anyway, if you let me know the engine code for the caddy and the age/code of the tfsi engine you want to install and I'll get you some diagrams then we can work from there
If your Caddy is a 2006 (model year, by VIN; not the irrelevant UK plate thing), then you want a 2006 or earlier MK5, to keep it easy. If both vehicles have the same Immo type (4A) then it's somewhat easy to sort the immo. 4C starts getting complicated... but mixing 4A and 4C is the most complicated way to do it! Starting with a SDI caddy complicates things; you'll want to use the suspension components from the GTI for the front, to get the bigger brakes and CVs etc, and convert the ABS to the GTI, with stability etc. I started my Touran R32 conversion when I was very new to "modern" VW's, but it's probably worth a look for what you're doing: https://forums.ross-tech.com/showthread.php?1649-NZ-Touran-wants-an-R32-engine Most of what I did (excluding the 4WD) is similar to what you'll need to do for a GTI conversion.
