Well I was planing on moding my B5 A4 1.8T some time in the future. I was going to do some things here and there and than finally upgrade the turbo. Well, things have changed. About a week ago I started to notice that my car was not accelerating as usual. Then a day later it wasn't accelerating at all. I knew what it was but I didn't want to come to a conclusion yet. So I took it to a local shop and had a guy test drive it. He came to the same conclusion as I did. My turbo was gone. I now have the first Audi A4 1.8. Well I could go ahead and put in a new KO3 but If I was planning to upgrade it later why spend money for a turbo Im just going to take out later. So my question is what would be a good turbo upgrade?
I have done tons of research but I didn't come up with much.

I have goten mixed reviews from the KO4. Does anyone here have one?