Hi,
Im wanting to swap me 1.8T ME7.5 to DSG, because reasons..
Since there are practically zero DQ250 4motions from a petrol car for sale here (Yes ive checked everywhere), i'm considering getting one from a diesel. Yes, i am aware of the issues with "taller" gearing etc.
Now the reason i come here for help, i have zero DSG tuning experience, i have done some ME7.5 tuning with success.
Game plan, flash my current ECU with an auto software, so ME7.5 parses the data given from the DSG.
Option 1: Retune the entire DQ250 to suit a petrol engine
Option 2: Reflash the DQ250 to petrol software, and redo the gear ratios, and some fine tuning (Not sure if this is possible)
Option 3: Get an petrol mechatronic and redo the gear ratios and fine tune.

Has anyone done something similiar to this before?

I'm sure im wrong in many ways but im keen to do it so want to hear others thoughts 

A Prj said its not as simple as just cooking up a file with mixed stock calibrations. I've done it a few times and the first time was a complete nightmare.
   

Guess i'll keep looking for an DQ250 from a petrol then.
In the worst case i guess i'll have to go down the nightmare route and redo alot of the shift maps etc on an petrol software to suit diesel gear ratios.
I'll be posting my findings here and maybe helping others later
I couldnt seem to find any solid information about someone redoing it for diesel ratios so guess ill start from scratch   

You can source two dq250's - one petrol fwd and a diesel 4wd, swap the front housing and differential assembly (as a whole, or just the big ring gear, depending if it has the same number of teeth) and it will be a proper petrol 4wd gearbox. I did exactly this, because it was much more financially effective than just buying a 4wd petrol dsg.
Up until I did that, I ran a 1.8tfsi dsg software with diesel gear ratios and modified shift maps etc., it was not ideal, but it was fine.