Looking to upgrade the exhaust on a MY01 WRX.

Should I decat the downpipe or the centre section?

I already have a STI back box fitted.

Not looking for huge power gains, or a lot of noise, just want to get a bit more of that flat four burble.

TSL recommend leaving the front cat for a bit more back pressure, but others recommend removing this and leaving the centre section!

All advice welcome.

Thanks in advance

 

looking back with hindsight if I wanted to be emmisions frieindly.....

I'd put in a de-cat downpipe and a high flow cat..... Haywood and scott do this set-up as do TSL.

Will pass MOT (apparantly) with better spool up / noise without mandatory re-map

Midlife.....

 

I Have gone all the way with the Terzo, Haywards & Scott down pipe & center section but kept the old center section for the MOT, only 4 bolts to fit center section 20 mins or so. loveley sound not too loud and a bit more power!!! (we like that) emisions stand at about 1% totally decatted fit the center section then right down below pass rate