For all you asking about this mod and what it does...
heres is the best way i can help.
when you get full headers or just a slip on or even with a stock exhaust set up, and a PC with a custom made MAP (without a PC and a CUSTOM map this mod is useless)there can be engine deceleration popping noises inside the headers from unburnt fuel passing threw. like backfire so to speak. this also causes presure to build up inside the headers which can cause damage to the engine and pipes. by removing the PAIR this will prevent this from happening.
is it necessary? NO
will this give you performance gains? NO
is this weight saving? YES, but less than 1 lb.
do you need plates? NO
simplest way to do this is to close the tube in the airbox and just conect both caps together on the block using the same hose.
will this give you a more accurate F/A reading? YES
but honestly this is normally for fine tunning a custom map, for the hardcore track guys or a track only bike.
will this have any gains on a street, non track bike? YES a little, but you probibly wouldnt notice it.
will this improve a basic map from dynnojet website? MAYBE
like i said if you are getting a custom dyno tune with a map, or a custom map made (without a dyno) for your bike and you have a PC this mod can be benificial.
This mod can also keep your bike on the safe side.