I'm contemplating on getting a Greddy SP2 and was wondering if this will fit a 3" flat-flanged downpipe (mine is a Perrin catless). I understand that the SP2 can be mated to a donut flanged downpipe (such as the stock one or Cobb) but am unsure whether this will securely connect with my downpipe. Will I need to modify the flange? I did use a search regarding this exhaust and the downpipes they're connected to but did not explicitly yield an answer to this issue. Please forgive me if this has been covered before and will appreciate your responses.

 

I do believe that you need would need an adapter to form a perfect fitment between a 3" dp and the 2.5" backend of the the GReddy SP2.

 

It will probably work. I mated the stock 2.5" sti exhaust to a aps 3" downpipe and using the smaller gasket, it did work as the bolts holes still line up. You should be fine

 

Thanks guys. It did work as I had it installed yesterday. The quiet sound is definitely to die for!