Its unlikely you will see that KZN 6wkw(5.17%) gain in JHB,
From my memory @
Die$eL tested his drop in filter at Schalks Conversions(Gauteng) in early 2014
and:
115wkw to 117wkw
Which is 2wkw (1.74%) gain,
In terms of sound getting louder, you can enhance this a
little with the TRD Sound Changer...(Could be a
mind gain as well...who knows)