The Booster Plug just plugs into the air temperature sensor, located on the airboot somewhere. It just fools the sensor to think the air is colder out than it really is, and therefore the ecu gives the bike more fuel. It's kind of like what we do with TPS tuning. We are just fooling the ecu in an effective manner.
Some chat site and internet dumb dumbs ( senior memeber on a forum just mean the idiot thats been spouting off crap the longest ) think TPS tuning is bad, but it's really not much different than this. They may frown on this too. But they also are 60 and live with thier mommies still.
So whether you use the programmer or this Booster plug and fuel regulator, you get all the great fueling you need, at 1/4 the price of the high dollar ECU's.