No codes yet, thankfully. I just think live monitoring would be a 'nice to have', giving me the ability to geek-out by playing with my engine through my phone.
I also don't have a tach, and have no intention of putting one in. But I'm genuinely curious what my cruising/idling RPMs are, so the ability to see that would be nice.
If I had one thing I'd change, it'd be to give my engine a lower idle RPM with a quicker return to idle from startup/warmup/etc. My I might get Garry to adjust it one of these days, just seems like such a trivial thing and I don't want to bother him at this point.
Good luck on the wiring, 71BroncoSport...