NefMoto

I have a mk5 GTI 2.0t FSI 6mt. 200k miles, still shifts like butter, but the FSI is tired (stage 2 most of its life, typical hardware upgrades) and I have no desire to do anything with it any longer, so any suggestion to do anything with the FSI will fall on def ears.  Not being smart, I just don't want to work with that engine.  In the recent past I acquired a '08 Jetta 2.5 (CBT, ME7.1.1) parts car, and was planning to use it for other purposes, but that ended up not happening.  The other day I started thinking about doing a bit of a budget build 2.5t for the mk5 GTI, and was curious if anyone had ever poked at a turbo 07k file, not TTRS. 

Ive done some reading, and I know the 06-07 Beetle ECU is the one to work with out of simplicity's sake.  But...  Ive done some experimenting with a prior project, and I'm 95% sure that mk5 and mk4 throttle pedals arent compatible.  I did a bunch of legwork to see about making a 1.8t work in the same GTI with the 2.5 donor cars wiring, and after taking a quick look at wiring diagrams and a little repining, the 1.8t ECU didnt seem to interpret the mk5's pedal inputs properly.  Although, I may need to do some more poking on that subject to be sure. 

I forget the number on the ecu I have, but I'm 99% sure its a ST10, not Infineon. I wouldn't mind going with a ME17, since it would require very little rewiring in the GTI, but I have nothing to read/write a ME17 ECU, unless a MED9 BDM is compatible.  I'd also have to get a new engine harness, and a few different sensors. 

My thoughts were to maybe look at some maps as found in a stock TTRS file, for ignition and such.  I imagine fuel maps would be different since its direct vs port injection.  But on the subject of making it understand that boost is a thing, i'm clueless. 

Any help and insight would be much appreciated. 

Based on questions you asked, I'll go with "forget it" advice. And that with absolutely no offense meant.

If you're absolutely certain on wanting to make this work - get a complete swap kit from TTRS (FSI, harness & ECU included).
You could also try stock ME7.1.1 & port injection. But you're in for a whole world of hurt to make that work properly. It's far more complicated than just altering some maps.

Not sure what the reward is going to be on this. If you want a turbo'd 5 pot, fit a TTRS engine and management. Far cheaper, easier and reliable in the long run than to turbo a 2.5 NA engine and make it work.