Well, my original plan was to match the Apex'i downpipe with a SARD sports catalyzer with my existing Blitz Nur Spec R exhaust. I have both items ordered but something went wrong with the order for the cat. So now I have a downpipe coming next week... Should I even bother installing the downpipe while still on the stock cat? Please give me advice!

 

downpipe on stock cat and turbo won't give you any gains, especially the Apexi which is non-02 housing.

 

so I guess if I dont get a HFC or test pipe then there wont be any point to install the downpipe...

 

I say do it. Here is why:

http://www.ultimate-racing.com/Produ...Downpipe.shtml

According to this there is ~7whp to be had with this particular car and it's setup.
oh and ~6ft.lbs


P.S. I understand that this is with a test pipe but the only change is the downpipe. The car should spool sooner ever so slightly.