You need to decide what you want the car to do. Is this long term street use where you need low down and midrange power? Or is this going to be a track car that you rev the nuts off of and need power at the upper end of the rev band? Then you need to get a turbo map of what you're looking to put on. Go Here
Read it learn it love it. You can spend 2-5 grand depending on what you finally decide on doing.