Originally Posted by ChesterWRX
wow, that exhaust looks really good. so the DP has two hi-flow cats and it's a full 3" TBE in this config.?
i like it. do they or did they advertise average gains from this set up? *just curious.
Just the one 300 cell metal substrate cat, the "second cat" is just a heat shield that might fool the casual observer into thinking the stock cat is still there.
They don't really advertise any gains other than saying you will see similar performance when compared to other high quality catted DPs. At stage 2, the rest of the exhaust doesn't matter a huge amount so the Whisper probably doesn't help/hurt there. If going with bigger mods down the road, I ordered the full 3" front to back (no donut gasket for DP connection) so it should flow pretty well. There's pages and pages of forum posts discussing DP design and which is superior (e.g. divorced wastegate vs bellmouth), but for what I'm doing I don't think it matters much.
One reason I decided to order the entire TBE package was so I would have a brand new, high quality, stainless steel exhaust that will hopefully make it through many upstate NY winters.