Levin Twin Muffler Exhaust System..

[wfhan]

been trying to find out some tech. spec on this
on how it works.. but to no avail, maybe my search keyword is dump so can't find any useful info..

Heard some said that there is a "valve control" somewhere to control the levin twin muffler exhaust.. isit ar?? sorry i donno cos i noobs...
isit when low rpm (low output) that time it only use one side of the muffler.. and when rpm hit certain range (high output ) it then will utilize both muffler for exhausting ??

and what is the effect from changing from a stock levin twin muffler to a single muffler type like RS*R/Apexi/FGK..etc...??
power gain ??

can some sifu explain ? or if got technical link.. pls provide..
thank u all first..