So a twin dump will fit, but a twin dump with a cat won't, right? My understanding is that you want to put the cat close to the engine so the higher heat activates the cat quicker and reduces emissions that much sooner. Do you know whether moving the cat downstream makes a difference in flow (in other words if the cat is cooler, does it flow as well?)?

 

The cat should flow just fine, but you are correct that the cat will work much better closer to the turbo (and heat).

Ya, the big problem with the 6MT is that the case is wider and most, if not all, downpipes with cats close to the turbo just don't fit. I would think you could use a smaller cat, but they may not exist or work as well and that's why companies just put the hiflow cat downstream.

 

Holy old thread bump.

So you went with Vishnu and heard bad things. Are you happy with what you got?

 

Vishnu Stg 0 to 2+ for over 70,000 miles nothing but reliability and power.... currently at 278whp ~100oct / 257whp ~ 91 oct. Compression still at factory specs with 88,000 mi on car. Original tranny.

 

I have a stg2 runs strong 275whp on 94 octane. No problems!
John

 

i have a stage stwo, everything is great but it is a lil pricy. but great products that are reliable arnt cheap either.

 

I had a 05 STI with the stage 1 package, it was very fast to say the least, good drivability, and high quality exhaust (taipan XP) which they no longer carry.