I'm new to FI and I love the stock sound. I know enough to get HF cats, but do I need to replace the exhaust cat back? I'm sure I can get a few more HP from a Stillen, but sound is important and I don't want anything too loud. I figure the OEM cats are the most restrictive part.

I can get a good used Stillen for a good price. Are the Stillens a lot louder than stock?

Thanks from an FI noob.

 

from what I hear, changing to the crawford cats will make the car louder than if you only changed to the stillen

the stock exhaust is fine for the vortech at low boost, in fact that's exactly what vortech made their base map tune for on the stock kit

I don't think you'll really be happy with the vortech though until you upgrade to the 3.12 pulley and do cats and exhaust
IMO the stock vortech kit on a near stock car isn't super impresive. You'll feel the boost really hard somewhere around 5000 rpms until redline, but below that the stock pulley just doesn't spool it up very much

 

So maybe I should go ahead and get the stillen exhaust. The guy with the vortech is also selling the stillen, just no HF cats.

No real boost below 5000 rpm isn't fun. Looks like a 3.12 pulley is in order.

 

yeah the 3.12 pulley lowers the big feeling of boost coming on to around 4500 rpms instead of 5000 rpms

 

well i have HKS + crawford cats on my z right now, but its too loud!
im goin back to stock cats, hoping itll be easier on the ears