TOPIC: Aftermarket Electronics and The Gadgetman Groove

There are many electronic components that are designed to enable a much leaner air fuel ratio. What we are trying to determine is:
What electronic parts may be used successfully with The Gadgetman Groove?
A) What effects can a user expect?
Does the application of such components need to take place BEFORE or AFTER
the ECU has adjusted?
Please discuss here if your vehicle has any such modification and what you have found with its use in conjunction with The Gadgetman Groove.