Andre, you need to make one thread about your build... You're putting information EVERYWHERE. Maybe a mod can merge the threads from his other posts all into one?
to answer your turbo question we first have to know what you're expecting from your motor.
Do you want a streetable setup, meaning less lag and possibly less top end power in the long run, or do you no mind some lag but want it to be a monster up top? how much HP do YOU want to make?
You cannot expect people to answer every question for you. If you're attempting a build like this you need to do a lot of research and choose a certain route to follow. There are a TON of people boosting your setup on bimmerforums.com, take a day out and search turbo M3, etc and you'll find more threads then you probably want to read. But it gives you a good idea as what to expect.
That said, answer my two above questions and we'll go from there. And stop making new threads