The elite 1500 is far superior to the sport series. From memory its a quad core processor instead of single, you can overlay 4d tables now too. You get the new elite software also and can log straight to usb.
We don't usually run knock control on any of the cars we do as its been average in the past and we have never had any problems.
We are a premium haltech dealer and have already done a few elites in the last week and a heap last year. In saying that most of the evos we tune are on std computers because it will do what you want and they dont really need anything better.