i've just upgraded my exhaust and i'm planning on replacing my cat. my stock converter is the 18" length one and i'm wondering if a 13.25" one will work and still provide legel emissions. the muffler that came with my exhaust was 3 inches too long anyway so i just plan on getting the 13.25" cat and having a muffler shop add on a few more inches to my muffler pipe to make it fit. plus the 13" cat is less than half the price of the 18" one. so does that sound like it would work?

 

I just asked the same question. Here is the link to my thread with some answers:

https://www.yotatech.com/forums/f2/good-catalytic-converter-52044/