Apologies if in wrong section, but needed a quick response.

I have a full decat on 02 STi, still got original up pipe, will I get any gains from changing to a flexi decat up pipe?

And I know I have spelt benefits wrong

 

dont think there is a cat on the up pipe

 

Porting and wrapping would see a benefit.

 

From what ive been told there's no Cat in the Sti models only the Wrx

You could by an after market up pipe the has an increased bore diameter but this would only make a small difference, My advice would be to fit a Replacment header and up pipe system to get the most from it.

 

Some good gen here

 

Give API a call for advice re this.