Question: what's the advantage of using the 200 bucks SAFCII over the EFIE or any other primative circuits, whichh corrects the O2 sensor signal , besides thhe looks and being able to have different settings for the RPM range?

 

These cars run on NB O2's and the o2's have no input @ WOT. The SAFC alters MAF signal, which does have input on AFR @ WOT, and that will affect WOT AFR.