Hi all, I have a 2005 Impreza STI with the PPP fitted and am looking for adviice on what options are open for me regarding exhausts.

Just want to check that the Prodrive system fitted with the PPP has only 1 cat in the downpipe and is a 2.5" system?

My reason for changing the exhaust system is that the car is running 337bhp at the moment and am looking to increase this to around the 450 mark & someone has advised that I would struggle with the standard exhaust system.

So, could I just remove the cat, would this be good enough

Or should I replace the centre section and back box with a 3" system and keep the standard downpipe but take the cat out.

Or do I really need to go for a full 3" system including downpipe.

Thanks Robert

 

I've just had a Prodrive exhaust put on my STi Hawkeye, and I'm pushing for 400BHP once I have run in my engine (just been re-built) it's getting mapped. I have a sports cat on mine. Surely this is what you need. I don't imagine that the backbox is going to hold you back, maybe the pipes from engine down to back box need to be replaced. I don't know though. I don't see why the guy who did mine would have bothered sourcing and putting the Prodrive exhaust system on when I'm going for a significant power upgrade. Like I say though, I don't know much!

 

Hi Guys, I was running the Prodrive exhaust on mine... Its in standard tune at the moment..... Ive just replaced it with a Ninja II cat back system.. The centre pipe doesnt have a cat in it, so when you remove the prodrive exhaust you remove the 3rd cat!
I have to say im pleased with the ninja II but the centre pipe runs very very close to the propshaft centre bearing and sometimes it does rattle a bit against it
Ive tried to adjust the position of the pipework, but i think im going to have to take of the centre pipe again and flatten a small section of it where it touches the bolts that hold the centre bearing on.....
I got the Ninja II from Ebay for a fraction of the original cost! yay.... it had only been fitted for a week before the guy wrote the car off!

 

if your trying to achieve 450 bhp from the standard 2.5" it will be come restrictive. probably better off with 3" mate.