I'm looking into this from a hobby/curiosity standpoint, and NOT a "big HP gains" standpoint. Would there be advantages to adding a wideband O2 sensor and some piggy back fuel controller (or something) to more accurately create a proper mixture?

I noticed that the n/a car goes open loop if I'm doing anything more than 2/3 throttle. Besides pollution and wasting fuel, is there any draw back to a rich mixture?

Would the wideband O2 system have a faster reaction time for adjusting mix, and thus more efficient fuel usage and power?

Apparently LEV2 vehicles are almost achieving wideband O2 functionality while still using a traditional cheaper narrow band O2 sensor by having a faster close loop process for adjusting fuel.

Just pondering. Inputs?