What is the purpose of a "booster plug" I'm limited in knowledge of things technical. 
New Euro 4 regulations for motorcycles dictate that engines have to run as lean as possible - at 14,7:1 air to fuel ratio (AFR) vs 13,6:1 which is the optimal stoic ratio for an engine. Most modern bikes suffer due to the consequences of lean mixtures: snatchy throttle, reduced low rpm usability, surging, pinging, motors running warmer, lethargic at lower rpm. From the new XDiavel to Yamaha's MT-7 or MT-9, BMW riders were first to realize that lean running affects engines and performance. A BoosterPlug is a plug and play device that modifies the AIT sensor to improve the AFR to optimal levels - just when you need it: acceleration, deceleration and a stronger idle and start. The beauty of the BoosterPlug is that, while it improves low rpm performance, it leaves the engine to be fuel efficient.