As far as I know changing the rear sports muffler back to original will make your high end slower as exhaust gas cannot go out fast enough. Maybe change to a quieter sports muffler mentioned by the members....

who is d installer / tuner?

some forummer suggest u to try mugen twin loop style muffler
i think his problem kinda major.. lol..even wit 2 muffler n s flow muffler, his gf still complain its loud..   
which shop/ tuner?

I had the same problem last time when use my turbo for outstation, at more then 110kmh, the drone of the muffler will get to you after some time. So later on, all outstation travel use wife's car.....

he has a huge problem la..lol.. even wit 2 bullet n 1 s flow muffler , somemore stock piping, his wife still complain.. i recommend u to ignore wat ur wife say...lol....

my car also loud drone sound when rev near to 4k rpm 5th gear... d speed is onli around 120... dats y when i fetch my wife, i capped my speed to around 90-100.. d rev is 3k rpm, so she no bising bising me..lol

he has a huge problem la..lol.. even wit 2 bullet n 1 s flow muffler , somemore stock piping, his wife still complain.. i recommend u to ignore wat ur wife say...lol....

my car also loud drone sound when rev near to 4k rpm 5th gear... d speed is onli around 120... dats y when i fetch my wife, i capped my speed to around 90-100.. d rev is 3k rpm, so she no bising bising me..lol

u r sayin midbox or oval muffler ?

I am using apexi but I don't know it's original o nt la... Very quite leh... A little bit bass only...

unless it's original mugen twin loop, else i guess it wont last long. saw tons of owner selling their used twin loop. what brand sflow you're using bro?

nope... can reduce noise pollution alot... but throttle response will reduce alot as well...

there is no such definite rule.

exhaust system is very passive with so many variables taken into account.

the important variables need to be considered
- exhaust flow smoothness
- piping size
- piping length

you have to bear in mind that resonators/bullet/midbox, mufflers and all the noise suppressors affect the exhaust gas flow in one or another way while helps reducing noise. if you have a very good muffler, it is not necessary to have additional midbox in the middle. you look at basic factory produced cars, a lot of them do not have bullet/midbox, only one rear muffler. Proton Wira 1.3/1.5 automatic for example, does not have any bullet or midbox.

remember, people want extra bullet or midbox in the middle to suppress noise, not to create performance. although to some extend the choice of resonator and placement does affect the power curve in some sort of way.

yes you can.

if removing it will cost you some labour charge, better just leave it. otherwise best to get it removed.

yes you can.

there is no such definite rule.

exhaust system is very passive with so many variables taken into account.

the important variables need to be considered
- exhaust flow smoothness
- piping size
- piping length

you have to bear in mind that resonators/bullet/midbox, mufflers and all the noise suppressors affect the exhaust gas flow in one or another way while helps reducing noise. if you have a very good muffler, it is not necessary to have additional midbox in the middle. you look at basic factory produced cars, a lot of them do not have bullet/midbox, only one rear muffler. Proton Wira 1.3/1.5 automatic for example, does not have any bullet or midbox.

remember, people want extra bullet or midbox in the middle to suppress noise, not to create performance. although to some extend the choice of resonator and placement does affect the power curve in some sort of way.

One thing for sure, if you're changing the bullet, avoid spiral/twisted type bullet because it's not only gimmick, but also create more 'droning noise'.