I currently have a 3" Milltek sportscat Downpipe mated to a catted and resonated centre and 4" exit backbox


Looking at the bills that came with the car i assume they are these parts
3" Single-scroll STI Milltek Downpipe with Resonator MSSUB133
3" Centre Section with Sports CAT and Silencer MSSUB127
3" Milltek Impreza Rear Silencer MSSUB128


If i leave the sportscat downpipe on but change the centre to a straight through would there be a noticable noise increase? It's too quiet at the mo'


Also anyone know if it has to be a milltek centre or can i get any 3" newage straight through pipe- ie from the nice and convenient people at H&S

 

yes it will be louder .

 

My car with cat but the rest back stainless - Nice burble.

My car after decat centre section fitted - Sets off car alarms when passing them.

 

Well went to Hayward & Scott and Ian fitted a bespoke 3" straight through centre for me - great workmanship as always!!

It isn't that much louder but it is on full chat which is what i am after - so pleased...

My previous JDM had a 3" full decat turbo back and that was 122dB so I'm guessing alot of the noise is generated when the downpipe cat is removed? Oh it also had a 5" exit this one only a 4".

I'll leave the DP sports cat in this one though - ease of MOT and (today) it's loud enough...

 

removing the centre will not increase the noise much anyways, i fitted 6 backboxes after turbo decat befor i was happy with the noise.
loud but not over the top.