Decided after it was (somewhat) fixed that since I've pumped so much money into it already that I could just be selling it to buy another car with just as many issues.
30th anniversary has the bigger K04 turbo, injectors, high pressure fuel pump etc etc. Yes and no. It would be a bonus if the oil consumption was fixed, but I'm looking more into the limitations of tuning with the stock turbo vs the one from the s3/30th anniversary/cupra. 280bhp is about the absolute max a K03 can handle whereas just a remap will send any of the cars listed above straight to 300. As I said for now it's purely just a shopping list, but having looked on a few forums the engine should cost around £1300, which is much cheaper than buying the parts separately and putting them on my engine.
Alternatively, I do have a massive hard on for jap cars every time I go to trax + recently Japfest2, so that maybe an option instead of tuning this car.