I plan on buying a Magnaflow cat for my car and I've found two that seem thebest options.

I'll be installing a 2.5" exhaust and I need a cat with 2.5" in/out. I found two that will work, but I don't know which will be a better fit due to thelength differences.

Because they are universal, they'll need to have the flanges welded on at both ends, but I wan't to make sure that I buy the right length. Magnaflow #91036 is 13" in total length and the #94036 is 16". The stock/direct fit cat is 16.25" in length.

Which one would be the better choicefor best fit? 13"since I need to weld the flanges on anyways (will probably need to weld a little pipe on too)or 16" if it will allow for the flanges to be added?

Thanks.

1996 Civic EX Coupe, d16y8