So my stock exhaust was pretty well shot. First I had upstream 02 issues and then I had a cat go bad. Luckily I came across a Nismo exhaust with only 35k for super cheap and I also bought some FI resonated high flow cats. Obviously I need extensions for the mid pipe.

My question is, would it make any difference if I put the extensions on the mid pipe or attached them to the cats thus pushing the H pipe back? Let me know your thoughts.

 

The extension needs to be done on the midpipe, otherwise it doesn't make sense and won't work.

 

Please explain. Is it because it moves the flex joints back? Otherwise it's the same pipe and there are no hangers, useable, on the H pipe as the Fi cats don't have brackets for the cross member bracket that connects to the tranny. Just wondering. Obviously I want to do it right

 

The midpipe and ypipe can only fit in the existing space under the transmission. There is no space for it further under the car.

 

Gotchya, that's what I was wondering. At work so couldn't look.

Extensions ordered. I hope that they don't rattle as the H pipe and mid pipe will come together just above a crossmember...