ryanec

I am upgrading my exhaust on my na. I have already bought headers and am wondering if I should take my cats off and what I should do about my resonators?

emo236

if you want to keep your hearing and legality, you should keep your cats and resonators. You can buy upgraded free flowing cats if you want. And most catback exhaust systems have resonators.

tnkrstoyco

Depending on where you live. I just changed to a new Borla exhaust and punched out the cats.

ryanec

How did you punch out the cats? Did it effect your sound or any difference in hour power?

b300z

take something long and poke around in your cats, or cut them open, gut them and weld them back together.

removing cats will drastically increase the decibel of your exhaust, lose a little low end, and gain a little top end

tnkrstoyco

Here's a small write up done by a friend while doing my vert.
http://www.zmods.org/index.php?page=catgut