Έστειλα μήνυμα και τους ρωτούσα να μου πούν,ποιός συνδιασμός είναι καλύτερος για να δουλέψει το μηχανάκι σωστά : α) Boosterplug με φίλτρο, β) Boosterplug με φίλτρο και τελικά ή γ) μόνο με Boosterplug;
  Η απάντησή τους για όποιον ενδιαφέρεται :

  Most aftermarket filters and exhausts will flow a lot more air at higher RPM, but at low RPM's the difference between the resistance in the original exhaust and the aftermarket system is minimal - so in low RPM conditions, the AFR (Air/Fuel Ratio) is almost the same.

In a modern fuel injected bike, there's no risk of damaging the engine by running it too lean when you install an aftermarket exhaust or K&N filter - because the O2 sensor in the exhaust will adjust the mixture back to the original AFR in all closed loop situations (Higher RPM)

(Medium and high RPM and steady throttle conditions are closed loop operation - see the BoosterPlug.com website for a full explanation on open loop and closed loop)

But as the aftermarket parts will flow slightly more air in low RPM conditions too, the drivability will be even worse than on the stock bike. Normally we see the open loop AFR go from around 14,4:1 to 14,5:1 with the aftermarket exhausts, and now you really need the small controlled fuel enrichment from the BoosterPlug to restore the smooth throttle action and to prevent the engine to stall easily.

So, the fact that the AFR difference (between the stock system and the aftermarket parts) is relatively small in open loop conditions,makes it possible for the BoosterPlug to cover all combinations of exhausts and filters on the bike. (The BoosterPlug is only active in open loop)

You are far worse off if you installed a Power Commander, where the O2 sensor is removed/bypassed and then changed the exhaust. Now you would have to dyno and set up the Power Commander correctly again to avoid running the engine too lean all the time - with the risk of damaging your engine. 

Sorry if this got a bit technical.