Please forgive my audacity for quoting Jake Raby previously, I do not speak for him. I have attached a thread that allows him to speak for himself. It contains much good information pertaining to this subject and was given for free. Yes some say he has his own agenda. I think his thoughts no longer on this forum is a great loss. YMMV.
http://986forum.com/forums/performance-technical-chat/21614-read-warned-about-your-motor-4.html