Digital A/F that shuts down boost

Don't think I could ever totally trust that as it still just uses your narrowband sensor so you only as good as whatever reading and shape its in. But I'm biased with my WB.
Your narrow band sensor is only really accurate at stoich.

So when doing tuning, I would rely on my O2 readings from my scanmaster and EGT guage. This is how its been done. And leaning the motor to what 670's?? it will live there as long as there isnt any KR.

What you need is a system that under knock retard shuts you down. Lean is easily fixed.. KR.. nah.. But thats why using the ecm to do your boost control has this benefit.

Save your money, watch your knock.. you'll be ok. Most of us that watch KR live a long time.