your midbox and muffler is still the stock one?

This is a common tactic by exhaust shops, they will change extractor first so that the annoying sound will appear. Then after a few days/weeks when you tak tahan the sound, then you will go back and change muffler. After changing muffler, you will then experience some "bunyi berdengung" from the middle of the car and then you're forced to change the center bullet also.

hello all.. im a newbie in exhaust and i basically dont know anything,

my ride satria neo 1.6 auto. so recently my catcon cracked and leak. so forcing me to changed it.

so i decided to change the extractor to 4-2-1, but only until middle section my muffler and silencer still remain the same.

my question is. when my rpm around 2000 it sound like leak, noise like turbo spooling.. but i have no turbo. isit  my backend dont support this extractor or this because it have some leak on the welding? according to my brother, who send the car to workshop that is because my back-end doesnt support the new extractor and there is not enough exhaust circulation. how true is this?