I can defeat the immobiliser in ME3.8 or ME7 to allow you to run the engine, AGU or later 1.8T. We have 2 MK1s converted in the workshop. They have no additional welded in strengthening. Both do run upper and lower strut braces though.

I am sure you will find a K03/s plenty fast enough with a tune. Dont make life hard by spending money on a K04-023. 200hp is mad in a MK1.

I have a 200kw atw Polo GTI, you dont want that in a MK1, it will pull it apart.

Gavin