Since David down under is advising against Avstar, I will chime in again. Been flying my new RV8 for about a month now. This is since my first post in this thread. Once again, I get book fuel flows on take off, EGT's peak nearly simultaneously, and very minor idle mixture tweaking RIGHT OUT OF THE BOX!!!! This has been our experience with at least a half dozen Avstars locally.
I will say that Don at Airflow Performance has always been very helpful whenever we have had issues with his systems.