And it seems that the average MPG get better with the plug.
Check this really well made review by WBW Booster Plug - webBikeWorld
After reading all of it, I think this is a pretty important if not the most important part.
"So Does It Work?
Having lived with lean-burn engines for years, a level of tolerance is the norm and like most other riders, the mind, body and right wrist adjust to the quirks so typical of some fuel injected engines.
Besides, living with lean-burn issues is far less painful when the ride is the multi-faceted F800GS -- my favourite motorcycle.
So, does it work? Definitely. Life aboard the 800 is much better with the Booster Plug. The first block ridden with it installed revealed positive changes; throttle action is now smoother, bumpy transitions are pretty much gone and the machine still creeps off at idle when the clutch is let out.
Throttle response, i.e., performance -- at least by the seat of my pants -- is improved and the unwanted back firing and pressure pulses, while not totally eliminated, are pretty much gone at any RPM or temperature.
The Booster Plug was installed two months ago and since then I have accumulated over 2000 kilometres or 1242 miles without any adverse effects.
Since being put on the road the fall of 2008, my F800GS has averaged 53.44 miles per Imperial gallon (5.28 litres/100 km), which converts to 44.49 miles per US gallon.
With the Booster Plug the average has increased slightly to 57.10 miles per Imperial gallon (4.95 litres/100 km), which converts to 47.54 miles per US gallon), all on my usual 93 or 94 octane gasoline and some 91 octane fill-ups..
This slight change could be attributed to many things, but I am confident that the Booster Plug is working well with the engine, including the closed loop fuel injection system used on the Beemer."