what diameter piping is used for the secondaries? Any difference b/t Stillen vs. Cattman?

what's the diameter of the piping after the collector/attaching to the main cat?

What's the diameter of the cat-con opening and exit?

What's the outlet diameter of the stock exhaust manifold?

How much can the stock exhaust manifold be 'opened' up? thick walled??

 

I've got a question on them too. I've heard this is a "bolt-on" mod, but what all is included in installation? Do you have to get the car up on jack stands or anything like that?

 

I can't answer any of the diameter questions but I can answer the installation question. Yes, you can install the Y on just ramps. I completely changed mine out in about 1 1/2 hours. Straight forward unjbolt and bolt back up. You will need a flex socket or extension to get to the second or back exhaust flange. The Stillen comes with everything included. I have Federal emissions so I didn't have to keep the front pre-cat.

 

Assuming the pix of the Stillen Y-pipe I've seen on their web site are the correct ones for our cars, their design looks to be the better b/t the 2 competing brands. I remember Nissan touting about the equal-length exhaust they use. The Stillen unit tries to emulate this.

So, were you able to see if the exhaust manifold inside diameter was the same as the stillen pipe opening?

What about the Cat-con opening? Same diameter??

 

Be careful about Stillen if you are concerned about the buzzing sound. When I researched this issue I found that only Cattman uses stainless steel (Stillen uses mild but they claim stainless) and Cattman's is quiet but Stillen's buzzes. Cattman is alot more expensive. I have mine in the garage waiting to be installed. I will let you know about the buzzing once installed.