Is a new ECM really needed?

[Idaho]

There seem to be plenty of warnings that a new Engine Control Module (ECM) will be needed when both pipes and intake are replaced because the engine will run leaner and could suffer damage. My experience with V-twins, albeit somewhat limited, is that they have a tendency to run too rich anyway. So my question is for those of you who have ignored conventional wisdom, and are quietly watching these discussions from the sidelines, who have installed new pipes and a BAK (big air kit) like the Caddmann mod and have NOT changed out the ECM. How many miles have you put on your bike with this combination and have you had any problems? Has anyone done this and destroyed an engine? Are there any test results that monitor tail pipe emissions and cylinder temps with this combo or is this just a seat of the pants wives tale?
Thanks again,
IDaho Nomad