I've owned a SAFC before, and we dyno tuned it to get accurately tuned per A/F ratio of my car,.. it was a N/A 300Z and the A/F curve was all over the map,... too lean down low, too rich in the middle, and too lean up top or vice versa ( can't remember, but it was way off ),.. and if I'm not mistaken, there's 2 settings, ... regular and WOT.